JP5924700B2 - Deblocking filtering control - Google Patents

Description

  The present embodiment generally relates to filtering control, and more particularly to control of deblocking filtering across block boundaries in a video frame.

  Deblocking filters are used in video coding standards to reduce blocking artifacts. Blocking artifacts appear because the original video frame is divided into blocks that are processed relatively independently. Blocking artifacts can appear due to, for example, intra prediction of various blocks, quantization effects, and motion compensation. Two specific variants of deblocking are described below.

  H. In modern video coding such as H.264, after prediction and residual reconstruction, but before storing the reconstruction for later reference when encoding or decoding subsequent frames, There is a deblocking filter, also called a loop filter. Deblocking filtering consists of several steps such as filter determination, filtering operation, clipping function and pixel value change. The decision whether to filter the boundary is made based on the evaluation of several conditions. Filter decisions depend on macroblock (MB) type, motion vector (MV) difference between neighboring blocks, whether neighboring blocks encoded residuals, and current and / or local structure of neighboring blocks .

  The amount of pixel filtering depends on, among other things, the location of this pixel relative to the block border or boundary and the quantization parameter (QP) value used for residual encoding.

The filter decision is based on comparing the three pixel differences with a threshold. The threshold is adapted to the quantization parameter (QP). For example, a, b, c and d represent the pixel values of the pixels in the row consisting of pixels in the current block, and e, f, g and h are in the corresponding row consisting of pixels in the neighboring block. Given the pixel value of the corresponding pixel,

abcd | efgh

Assume a vertical block boundary consisting of The filter decision is affirmative if the following conditions are met, for example, when thr1 and thr2 are adapted based on QP, abs (d−e) <thr1, abs (cd) <thr2, And abs (ef) <thr2.

  H. H.264 has two filtering modes. In a first filtering mode, referred to as standard filtering, filtering can be described using the delta value that is used when filtering changes the current value. The filtering for the pixel closest to the block boundary is d '= d + delta and e' = e-delta, and delta is clipped to the threshold ± thr3 for values constrained by QP. Thereby, more filtering is allowed for high QP than for low QP. Clipping may be described as delta_clipped = max (−thr3, min (thr3, delta)) when thr3 controls the filter strength. A larger value of thr3 means that filtering is stronger, that is, a stronger low-pass filtering effect may occur.

  The filter strength may be increased even when one of the following two conditions is satisfied, for example, abs (b−d) <thr2 and abs (eg−g) <thr2. The filter strength is adapted by not clipping the delta too much, for example by allowing more variation.

  A second filtering mode, referred to as strong filtering, is applied only for intra macroblock boundaries when the following condition abs (d−e) <thr 1/4 is satisfied.

  H. For more information on deblocking filtering in H.264, see List et al., “Adaptive Deblocking Filter”, IEEE Transactions on Circuits and Systems for Video Technology, vol. 13, no. 7, Refer to July 2003.

HEVC (High Efficiency Video Coding) Specification Proposal “Test Model under Consideration”, ITUT SG16 WP3 Document, JCTVC-B205, Chapter 6.5 In the in-loop filter process, the deblocking filter is H.264. It works differently from H.264. Filtering is performed if at least one of the blocks on the boundary side is intra or has non-zero coefficients, or if the difference between the motion vector components of the block is greater than one integer pixel. The For example, for i = 0... 7 and j = 0... 3, pj _i represents the pixel value of pixel number j of row number i in the current block, and qj _i is the row number in the neighboring block. If the pixel value of pixel number j of i is represented, the vertical block boundary is

p3 _i p2 _i p1 _i p0 _i | q0 _i q1 _i q2 _i q3 _i

When filtering the borders between blocks that are β as QP dependent, the following conditions:

d = | p2 ₂ −2 × p1 ₂ + p0 ₂ | + | q2 ₂ −2 × q1 ₂ + q0 ₂ | + | p2 ₅ −2 × p1 ₅ + p0 ₅ | + | q2 ₅ −2 × q1 ₅ + q0 ₅ | < β

Should be satisfied further. In the above-mentioned HEVC specification, there is a table of β, and β increases with QP.

If the condition is met and filtering is performed between the current block and neighboring blocks, one of two types of filtering, referred to as weak filtering and strong filtering, respectively, is performed. The choice between strong filtering and weak filtering is done separately for each line depending on the following conditions: For each line i = 0... 7, strong filtering means that t _c and β depend on QP and if >> represents a right shift operator, all of the following conditions:

d <(β >> 2)
(| P3 _i −p0 _i | + | q0 _i −q3 _i |) <(β >> 3)
| P0 _i −q0 _i | <((5 × t _c +1) >> 1)

If is true, a weak filter rig is performed otherwise.

Weak filtering is performed based on the above conditions. The actual filtering works by calculating an offset (Δ), adding this offset to the original pixel value, and clipping the sum to the filtered output pixel value in the range 0-255:

Δ = Clip (−t _c , t _c , (13 × (q0 _i −p0 _i ) + 4 × (q1 _i −p1 _i ) −5 × (q2 _i −p2 _i ) +16) >> 5))
p0 _i = Clip _0-255 (p0 _i + Δ)
q0 _i = Clip _0-255 (q0 _i -Δ)
p1 _i = Clip _0-255 (p1 _i + Δ / 2)
q0 _i = Clip _0-255 (q1 _i −Δ / 2)

Here, the clip function Clip (A, B, x) is Clip (A, B, x) = A if x <A, and Clip (A, B, x) if x> B. If x) = B and A ≦ x ≦ B, then Clip (A, B, x) = x is defined, and Clip _0-255 (x) is defined as Clip (0, 255, x). Is done.

The strong filtering mode has the following calculation steps:

p0 _i = Clip _0-255 ((p2 _i + 2 × p1 _i + 2 × p0 _i + 2 × q0 _i + q1 _i +4) >> 3)
q0 _i = Clip _0-255 ((p1 _i + 2 × p0 _i + 2 × q0 _i + 2 × q1 _i + q2 _i +4) >> 3)
p1 _i = Clip _0-255 ((p2 _i + p1 _i + p0 _i + q0 _i +2) >> 2)
q1 _i = Clip _0-255 ((p0 _i + q0 _i + q1 _i + q2 _i +2) >> 2)
p2 _i = Clip _0-255 ((2 × p3 _i + 3 × p2 _i + p1 _i + p0 _i + q0 _i +4) >> 3)
q2 _i = Clip _0-255 ((p0 _i + q0 _i + q1 _i + 3 × q2 _i + 2 × q3 _i +4) >> 3)

It is executed by.

  HEVC deblocking filtering decisions can cause inaccurate deblocking filtering across block boundaries for a particular block. Specifically, neighboring blocks with various levels of local structure are inaccurate in HEVC by over-filtering one of the blocks, thereby suppressing and filtering out local structures in the block. May be handled.

List et al., “Adaptive Deblocking Filter”, IEEE Transactions on Circuits and Systems for Video Technology, vol. 13, no. 7, July 2003 HEVC (High Efficient Video Coding) Specification Proposal “Test Model underification”, ITU-T SG16 WP3 Document, JCTVC-B205, Chapter 6.5 In-Loop Filter Process

  There is a need for an efficient deblocking filtering control that can be used to reduce blocking artifacts at block boundaries and does not have the aforementioned drawbacks.

  It is a general goal to provide efficient deblocking filtering control.

  Providing asymmetric filtering decisions across block boundaries is a particular goal.

An aspect of the embodiment relates to a filtering control method that can be applied to a block including a plurality of pixels in a video frame in which each pixel has a respective pixel value. In this method, p0 _i represents the pixel value of the pixel closest to the block boundary to the neighboring block consisting of a plurality of pixels in the video frame in the first line consisting of the pixels in this block; p1 _i represents the pixel value of the second closest pixel to the block boundary in the first line of pixels, and p2 _i is the third pixel in the block boundary of the first line of pixels. The first filter decision value for the block is calculated based on at least | p2 _i -2p1 _i + p0 _i |. In this method, q0 _i represents the pixel value of the pixel in the neighboring block closest to the block boundary in the corresponding first line consisting of the pixels in the neighboring block, and q1 _i represents the correspondence consisting of the pixel. Represents the pixel value of the pixel in the neighboring block that is second closest to the block boundary, and q2 _i is the third pixel at the block boundary in the corresponding first line of pixels. The second filter decision value for the block is further calculated based on at least | q2 _i -2q1 _i + q0 _i |. The first filter decision value is used to determine the number of pixels in the line of pixels in the block to be filtered with respect to the block boundary, and the second filter decision value is relative to the block boundary. Similarly, it is used to determine the number of pixels in the corresponding line of pixels in neighboring blocks to be filtered.

Another aspect of the embodiment is that a pixel of a pixel whose p0 _i is closest to a block boundary to a neighboring block composed of a plurality of pixels in a video frame in a first line composed of pixels in this block. P1 _i represents the pixel value of the pixel second closest to the block boundary in the first line of pixels, and p2 _i represents the block in the first line of pixels. If the pixel value of the pixel closest to the boundary is expressed, the first filter determination value for the block composed of a plurality of pixels in the video frame is calculated based on at least | p2 _i -2p1 _i + p0 _i | A filtering control device comprising a first decision value calculator configured to do is defined. In the filtering control device, q0 _i represents the pixel value of the pixel in the neighboring block closest to the block boundary in the corresponding first line consisting of the pixels in the neighboring block, and q1 _i consists of the pixel. In the corresponding first line, the pixel value of the pixel in the neighboring block that is second closest to the block boundary is represented, and q2 _i is 3 in the block boundary in the corresponding first line of pixels. The second filter decision value for the block is calculated based on at least | q2 _i -2q1 _i + q0 _i | if the pixel value of the pixel in the nearest neighboring block is represented. And 2 decision value calculators. The first pixel determination unit is configured to determine the number of pixels in a line including pixels in a block to be filtered with respect to a block boundary based on the first filter determination value calculated by the first determination value calculator. Is configured to determine. The filtering control apparatus counts the number of pixels in a corresponding line including pixels in neighboring blocks to be filtered with respect to the block boundary based on the second filter determination value calculated by the second determination value calculator. A second pixel determiner configured to determine.

  A further aspect of the embodiment relates to an encoder comprising a filtering controller as described above and a decoder comprising a filtering controller as described above. Yet another aspect is a memory configured to store a video frame and a code with a filtering controller as described above for encoding the video frame into an encoded video frame stored in the memory. A user equipment comprising a generator. A further aspect comprises a memory configured to store an encoded video frame and a filtering controller as described above for decoding the encoded video frame into a decoded video frame. A user equipment comprising a decoder is defined. The media player of the user equipment is configured to render the decoded video frame into video data representation that can be displayed on the display.

Yet another aspect relates to a computer program for filtering control of a block consisting of a plurality of pixels in a video frame in which each pixel has a respective pixel value. When the computer program runs on the computer, the pixel whose p0 _i is closest to the block boundary to the neighboring block consisting of a plurality of pixels in the video frame in the first line consisting of the pixels in this block In the first line consisting of pixels, p1 _i represents the pixel value of the second closest pixel to the block boundary, and p2 _{i in} the first line consisting of pixels If the pixel value of the pixel closest to the block boundary is represented, the code means for causing the computer to calculate the first filter decision value for the block based on at least | p2 _i -2p1 _i + p0 _i | Prepare. The computer in the first line q0 _i corresponding consists pixels in neighboring blocks represent pixel values of pixels neighboring block that is closest to the block boundary, the corresponding q1 _i is composed of pixels In the first line, the pixel value of the pixel in the neighboring block that is second closest to the block boundary is represented, and q2 _i is third in the block boundary in the corresponding first line of pixels. Assuming that the pixel values of pixels in neighboring blocks that are close to each other are expressed, the computer further includes code means for calculating a second filter decision value for the block based on at least | q2 _i -2q1 _i + q0 _i |. The computer program causes the computer to determine the number of pixels in a line composed of pixels in the block to be filtered with respect to the block boundary based on the first filter determination value, and based on the second filter determination value Code means for determining the number of pixels in the corresponding line made up of pixels in neighboring blocks to be filtered with respect to the block boundary.

  Embodiments implement asymmetric deblocking decisions that control deblocking filtering to accommodate structures on both sides of the block boundary. This asymmetry determination can cause the amount of filtering applied to one side of the block boundary to differ from the amount of filtering applied to the other side of the block boundary, thus making further adaptation to the local structure. Means. This improves objective and subjective video quality.

  The invention, together with further objects and advantages of the invention, may be best understood by referring to the following description, taken in conjunction with the accompanying drawings.

It is a flowchart of the method of the filtering control by embodiment. FIG. 6 illustrates an embodiment of neighboring blocks and block boundaries that can be deblocked and filtered. FIG. 6 illustrates an embodiment of neighboring blocks and block boundaries that can be deblocked and filtered. FIG. 2 is a flowchart illustrating additional selectable steps of the method in FIG. 1 according to an embodiment. It is the flowchart which showed embodiment of the determination step in FIG. FIG. 6 is a flow chart illustrating additional selectable steps of the method in FIG. 1 according to another embodiment. 2 is a flow chart illustrating an embodiment of additional selectable steps of the method in FIG. 1 and the determining step in FIG. FIG. 2 is a flowchart illustrating additional selectable steps of the method in FIG. 1 according to an embodiment. It is a schematic block diagram of embodiment of a filtering control apparatus. It is a schematic block diagram of another embodiment of a filtering control apparatus. FIG. 3 is a schematic block diagram of a further embodiment of a filtering control device. It is a schematic block diagram of another embodiment of a filtering control apparatus. It is a schematic block diagram of the software implementation of the filtering control apparatus in the computer by embodiment. It is a schematic block diagram of the encoder by embodiment. FIG. 3 is a schematic block diagram of a decoder according to an embodiment. It is a schematic block diagram of the user equipment by embodiment. FIG. 6 is a schematic block diagram of a user equipment according to another embodiment. 1 is a schematic diagram of a portion of a communication network comprising a network device according to an embodiment.

  Throughout the drawings, the same reference numerals are used for similar or corresponding elements.

  Embodiments generally relate to filtering control and deblocking filtering control across block boundaries in a video frame. The filtering control of the embodiment provides an asymmetric deblocking decision with respect to block boundaries by making independent filtering decisions on blocks of pixels separated by block boundaries. This allows deblocking filtering to handle neighboring blocks with various levels of local structure, thereby adapting the specific deblocking filtering in each block based on the local structure of each block Means that.

  As is well known in the art, a video frame is divided into non-overlapping blocks of pixels that are encoded and decoded according to various available intra and inter coding modes. . In general, a video frame is divided into 16 × 16 pixel non-overlapping macroblocks. Such a macroblock may then be divided into smaller blocks of various sizes, eg 4 × 4 or 8 × 8 pixels. However, according to the embodiment, rectangular blocks such as 4 × 8, 8 × 4, 8 × 16 or 16 × 8 are also conceivable. Embodiments can be applied to blocks of any such pixels, including macroblocks or blocks of larger pixels.

  In the emerging high efficiency video coding (HEVC) standard, a coding unit (CU), a prediction unit (PU) and a transform unit (TU) are used. The prediction unit is defined inside the coding unit and includes an intra or inter prediction mode. The transform unit is defined inside the coding unit, the maximum transform size is 32 × 32 pixels, and the minimum size is 4 × 4 pixels. The CU size currently varies from 64 × 64 pixels (maximum) to 8 × 8 pixels (minimum). In this way, the maximum CU can be divided into smaller CUs using a “granularity” that depends on the local characteristics of the frame. That is, the maximum CU can be divided into smaller CU groups of various sizes. Embodiments can also be used with such coding units, and these coding units are considered to be covered by the expression “block of pixels” as used herein. It is.

  Each pixel in the block has a respective pixel value. In a video frame, generally, color values are assigned to pixels, and the color values are expressed in a clear color format. One commonly used color format is one that uses a red, green, and blue component for each pixel, but one luminance component and two color components for each pixel. use.

  Traditionally, luminance component filtering and chrominance component filtering are performed separately, utilizing different filtering decisions and different deblocking filters if possible. However, the luminance filtering decision is H.264. As with H.264, it can be used in color difference filtering. Embodiments can be applied to filtering control for luminance components, chrominance components, or both luminance and chrominance components. In a specific embodiment, the embodiment is applied to control luminance or chrominance filtering. A filtering decision for one component, such as luminance, or a portion of the filtering decision can then be used when making a filtering decision for other components, such as color differences.

  Deblocking filtering is performed across boundaries, edges or borders between neighboring blocks. As a result, such a boundary may be a vertical boundary 1 between two neighboring blocks 10, 20 that lie side by side in the video frame, see FIG. 2A. Alternatively, the boundary is a horizontal boundary 1 between two neighboring blocks 10, 20 where one block 10 is positioned above the other block 20 in the video frame, see FIG. 2B . In a specific embodiment, the vertical boundary is filtered starting with the leftmost boundary first in geometric order and moving the boundary toward the right hand side. Next, the horizontal boundary is filtered in geometric order starting from the top boundary and moving toward the bottom. Embodiments, however, are not limited to this specific filtering order, but may actually be applied to any predetermined order. In a specific embodiment, the boundaries at the edges of the video frame are preferably not filtered and consequently excluded from deblocking filtering.

FIG. 1 is a flowchart of a filtering control method applicable to a block composed of a plurality of pixels in a video frame according to an embodiment. The method of FIG. 1 generally begins at step S1, where p0 _i is a plurality of pixels 21, 23 in a video frame in a first line consisting of pixels 11, 13, 15, 17 in block 10. , 25, 27 represents the pixel value of the pixel 11 closest to the block boundary 1 to the neighboring block 20, and p1 _i is in the first line 12 consisting of the pixels 11, 13, 15, 17 Represents the pixel value of the pixel 13 that is second closest to the block boundary 1, and p2 _i is third closest to the block boundary 10 in the first line 12 consisting of the pixels 11, 13, 15, and 17. If the pixel value of the pixel 15 is represented, the first filter determination value is calculated based on at least | p2 _i -2p1 _i + p0 _i |.

Step S2 similarly calculates a second filter decision value for the block based on at least | q2 _i -2q1 _i + q0 _i |, where q0 _i is the pixel 21, 23, 25, 27 represents the pixel value of the pixel 21 in the neighboring block 20 closest to the block boundary 1 in the corresponding first line 22 composed of 27, and q1 _i is composed of the pixels 21, 23, 25, and 27. In the corresponding first line 22, the pixel value of the pixel 23 of the neighboring block 20 that is second closest to the block boundary 1 is represented, and q2 _i corresponds to the corresponding pixel 21, 23, 25, 27. In the first line 22, the pixel value of the pixel 25 in the neighboring block 20 that is the third closest to the block boundary 1 is represented.

  The first line 12 composed of the pixels 11, 13, 15, and 17 in the block 10 and the corresponding first line 22 composed of the pixels 21, 23, 25, and 27 in the neighboring block 20 are on the vertical boundary 1. The horizontal line consisting of the same pixels extending above, i.e. belonging to a row consisting of pixels, see Fig. 2A, or the vertical line consisting of the same pixels extending above the horizontal boundary 1, i.e. belonging to a column of pixels, See FIG. 2B. Therefore, the first line 12 composed of the pixels 11, 13, 15, 17 and the corresponding first line 22 composed of the pixels 21, 23, 25, 27 are between the block 10 and the neighboring block 20. It is perpendicular to block boundary 1. Further, the first line 12 including the pixels 11, 13, 15, and 17 in the block 10 and the corresponding first line 22 including the pixels 21, 23, 25, and 27 in the neighboring block 20 are the same line. Have a number. For example, if block 10 and neighboring block 20 each comprise a row or column of N pixels having row or column numbers i = 0... N−1, such as 8 pixels 11, 13, The first line 10 consisting of 15 and 17 has the line number i in the block 10, and the corresponding first line 20 consisting of the pixels 21, 23, 25 and 27 is similarly line number i in the neighboring block 20. Have Thus, the first line 12 composed of the pixels 11, 13, 15, and 17 in the block and the corresponding first line 22 composed of the pixels 21, 23, 25, and 27 in the neighboring block 20 are: These are the opposing lines with respect to block boundary 1.

  According to the embodiment, the “line consisting of pixels” and the “corresponding line consisting of pixels” are “rows consisting of pixels” and “corresponding rows consisting of pixels” in the case of a vertical block boundary as shown in FIG. 2A. In the case of a horizontal block boundary as shown in FIG. 2B, “columns composed of pixels” and “corresponding columns composed of pixels” are represented.

  The first line 12 composed of the pixels 11, 13, 15, and 17 and the corresponding line 22 composed of the pixels 21, 23, 25, and 27 may be predetermined lines in the block 10 and the neighboring block 20, respectively. . Thus, the first line 12 consisting of the pixels 11, 13, 15, 17 and the corresponding line 22 consisting of the pixels 21, 23, 25, 27 are predetermined for each block boundary 1 to which the filtering control is applied, And it has a fixed line number i. Alternatively, the first line 12 consisting of pixels 11, 13, 15, 17 and the corresponding first line 22 consisting of pixels 21, 23, 25, 27 are the current line and the current corresponding line, respectively. This is described further in this document.

  The calculation of the first filter decision value in step S1 and the calculation of the second filter decision value in step S2 can be performed in series in any order, ie step S1 precedes step S2. Alternatively, step S2 precedes step S1, or at least partially parallel. The result of these two steps S1, S2 is thus the first decision value calculated based on the pixel values in block 10 and the neighboring block 20 on the opposite side of block boundary 1 relative to block 10 This is a second filter determination value calculated based on the pixel value. More preferably, the calculation of the first decision value is performed based solely on the pixel values in block 10 and thus not based on any pixel values in neighboring block 20. Similarly, the second filter decision value is preferably performed based on only the pixel values in the neighboring block 20, and thus not based on any pixel values in the block 10.

  The first filter decision value calculated in step S1 then determines the number of pixels in the line 12 of the pixels 11, 13, 15, 17 in the block 10 to be filtered with respect to the block boundary 1. Is used in step S3. The second filter decision value is used to determine the number of pixels in the corresponding line 22 consisting of the pixels 21, 23, 25, 27 in the neighboring block 20 to be filtered with respect to the block boundary 1 in step S4. In the same way. In this way, separate filter decision values are calculated for either or both portions of the row or column of pixels that extend over the block boundary 1, and each filter decision is for each side or portion. Is adopted for each side or part based on the specific filter decision value calculated in the above.

  This is a single or set of filter decision values calculated for a line of pixels and a corresponding line of pixels, and this filter decision value or set of filter decision values should be filtered on both sides of the block boundary It should be compared with the prior art used to determine the number of pixels. In this way, in the prior art, the same number of pixels is always filtered for the corresponding line of pixels in the neighboring block as performed for the line of matching pixels in the block.

  This embodiment instead has a separate filter decision for line 12 of pixels 11, 13, 15, 17 in block 10 and a corresponding line 22 consisting of pixels 21, 23, 25, 27 in neighboring block 20. Making a variety of different filter decisions for allows asymmetric filtering control and deblocking filtering. This is based on the specific first and second filter decision values and the number of pixels in the corresponding line 22 consisting of the pixels 21, 23, 25, 27 selected for deblocking filtering and correction. This means that the number of pixels in the line 12 consisting of different or equal numbers of pixels 11, 13, 15, 17 can be selected for deblocking filtering and correction.

In general, in this document, pX _y represents the pixel value of pixel number X relative to block boundary 1 in a line consisting of pixels having line number y in block 10. Similarly, qX _y represents the pixel value of pixel number X relative to block boundary 1 in the corresponding line consisting of pixels having line number y in neighboring block 20.

  Steps S3 and S4 can be performed in any order in series or at least partially in parallel.

  In the first embodiment, steps S1 and S2 can be performed once for a given block boundary 1 between block 10 and neighboring block 20, so that in block 10 The first filter decision value and the first filter decision value that can be applied to all the lines 12 composed of the pixels 11, 13, 15, 17 and all the corresponding lines 22 composed of the pixels 21, 23, 25, 27 in the neighboring block 20, respectively. 2. Calculate the filter decision value of 2. In such an approach, the same first number of pixels is preferably filtered and modified in each line 12 consisting of pixels 11, 13, 15, 17 in block 10 with respect to block boundary 1, where Thus, the first number is determined based on the first filter determination value calculated in step S1. Similarly, the same second number of pixels is preferably filtered and corrected in one corresponding line 22 consisting of pixels 21, 23, 25, 27 in neighboring block 20 with respect to block boundary 1 Here, the second number is determined based on the second filter determination value calculated in step S2.

  Alternatively, in the second embodiment, the first filter decision value and the second filter decision value are a subset of the line 12 consisting of the pixels 11, 13, 15, 17 in the block 10 and in the neighboring block 20. Applicable to a corresponding subset of the corresponding line 22 consisting of pixels 21, 23, 25, 27. For example, the filter decision value pair includes the first four lines 12 including the pixels 11, 13, 15, and 17 in the block and the first four lines including the pixels 21, 23, 25, and 27 in the neighboring block 20. And another pair of filter decision values can be used for the remaining four lines 12 consisting of pixels 11, 13, 15, 17 in the block, and neighboring blocks. Used for the remaining four corresponding lines 22 consisting of the pixels 21, 23, 25, 27 in 20.

  In the third embodiment, the calculation in step S1 is performed for each line 12 consisting of pixels 11, 13, 15, 17 in block 10, and a separate determination in step S3 is then performed for pixels 11, 13, 15, It is executed for every 17 lines 12 such as this. In such a case, the calculation in step S2 is similarly performed for each corresponding line 22 composed of pixels 21, 23, 25, and 27 in the neighboring block 20, and the separate determination in step S4 is performed for pixels 21, 23, It is executed for each such corresponding line 22 consisting of 25, 27.

  In this manner, in the third embodiment, step S3 includes the pixels 11, 13, 13 in the block 10 to be filtered with respect to the block boundary 1 based on the first filter determination value calculated in step S1. Determining the number of pixels in the first line 12 comprising 15 and 17. Step S4 is a corresponding first line comprising pixels 21, 23, 25, 27 in the neighboring block 20 to be filtered for block boundary 1 based on the second filter decision value calculated in step S2. Determining the number of pixels in 22.

The following part explains how the third embodiment is applied separately for each line (row or column) crossing the block boundary 1. In this example, the first filter decision value is
d _pi = | p2 _i -2p1 _i + p0 _i |
And the second filter decision value is
d _qi = | q2 _i -2q1 _i + q0 _i |
Is defined as This method consequently comprises:

Calculate d _pi and d _qi for each line i that crosses the block boundary.
If d _pi <thr1,
O Perform standard filtering on line i of the current block 10, eg filter and modify two pixels from the block border or boundary.
If not, i.e. d _pi ≥ thr1,
O Do not filter the second pixel from the block border or boundary of line i of current block 10 or do not filter the pixels on line i of current block 10 at all.
If d _qi <thr2,
Perform standard filtering of line i of neighboring block 20, filter and correct for example two pixels from block border or boundary 1.
If not, i.e. d _qi ≥ thr2,
O Do not filter the second pixel from the block border or boundary 1 of line i of neighboring block 20, or do not filter the pixels on line i of neighboring block 20 at all.

  As shown by the above example, the third embodiment of the method in FIG. 1 computes separate first and second filter decision values, so that for block boundary 1, block 10 and the neighborhood A separate determination of the number of pixels to be filtered for each row or column in block 20 can be made. As described above, in the third embodiment, the first and second filter determination values are filter determination values specific to the line, that is, each line including the pixels 11, 13, 15, and 17 in the block 10. 12 and for each corresponding line 22 consisting of pixels 21, 23, 25, 27 in the neighboring block 20.

  In the first embodiment, block specific filter decision values are used. Thus, in such a case, a single first filter decision value is calculated for block boundary 1 for block 10 and consists of pixels 11, 13, 15, 17 in block 10 for specific block boundary 1 It can be applied to all lines 12. Similarly, a single second filter decision value is calculated for neighboring block 20 for block boundary 1 and all of the pixels 21, 23, 25, 27 in neighboring block 20 for particular block boundary 1 It is possible to apply to the corresponding line 22.

The first example of the first embodiment includes calculating a first filter decision value as | p2 ₂ −2p1 ₂ + p0 ₂ | + | p2 ₅ −2p1 ₅ + p0 ₅ |, where p0 ₂ Represents the pixel value of the pixel closest to the block boundary 1 in the first line of pixels, and p12 is the _second value on the block boundary 1 in the first line of pixels. It represents a pixel value of a pixel in proximity to, p2 _2, within the first line of pixels represents the pixel values of pixels that are close to the third block boundary 1, p0 ₅ is block 10 represents the pixel value of the pixel closest to the block boundary 1 in the second line of pixels within 10, and p1 ₅ is 2 at the block boundary 1 in the second line of pixels. represents a pixel value of a pixel in proximity to the second, p2 ₅ is Among the second line consisting of hydrogen, representing pixel values of pixels that are close to the third block boundary 1.

The second filter decision value is then preferably calculated as | q2 ₂ −2q1 ₂ + q0 ₂ | + | q2 ₅ −2q1 ₅ + q0 ₅ |, where q0 ₂ corresponds to the corresponding _{second number} of pixels. 1 represents the pixel value of the pixel in the neighboring block 20 that is closest to the block boundary 1, and q12 is ₂ to the block boundary 1 in the corresponding first line of pixels. It represents a pixel value of a pixel around the block 20 in proximity to the second, q2 _2, within the first line corresponding of pixels, around the block 20 in proximity to the third block boundary 1 Q0 ₅ represents the pixel value of the pixel in the neighboring block 20 that is closest to the block boundary 1 in the corresponding second line of pixels in the neighboring block 20; q1 ₅ is, whether the pixel In a second line corresponding consisting represents a pixel value of a pixel around the block 20 in proximity to the second block boundary 1, q2 _5, within the second line corresponding of pixels, The pixel value of the pixel in the neighboring block 20 that is the third closest to the block boundary 1 is represented.

  The first filter decision value is then used for all lines 12 consisting of pixels 11, 13, 15, 17 in block 10 when determining the number of pixels to be filtered, and the second filter The determined value is used for all the corresponding lines 22 consisting of the pixels 21, 23, 25, 27 in the neighboring block 20 when determining the number of pixels to be filtered.

  In this first example of the first embodiment, the first line of pixels corresponds to line i = 2, the corresponding first line corresponds to the corresponding line i = 2, and from the pixel This second line corresponds to line i = 5, and the second corresponding line corresponds to corresponding line i = 5. In this case, the block 10 preferably consists of 8 lines, and the neighboring block 20 preferably likewise consists of 8 lines, i.e. i = 0-7.

The following part shows an implementation example of the first embodiment. In this implementation example, the first filter decision value is defined as d _p = | p2 ₂ −2p1 ₂ + p0 ₂ | + | p2 ₅ −2p1 ₅ + p0 ₅ |, and the second filter decision value is d _q = | Q2 ₂ −2q1 ₂ + q0 ₂ | + | q2 ₅ −2q1 ₅ + q0 ₅ |

● Calculate the _{d p,} to calculate the _{d q.}
If d _p <thr1,
O Perform standard filtering of the current block 10, eg filter and modify two pixels from the block border or boundary.
● Otherwise, that is, when d _p ≧ thr1,
O Do not filter the second pixel from the block border or boundary 1, or do not filter the pixel at all.
If d _q <thr2,
Perform standard filtering of neighboring blocks 20, for example, filter and correct two pixels from block border or boundary 1.
If not, i.e. d _q ≥ thr2,
O Do not filter the second pixel from the block border or boundary 1, or do not filter the pixel at all.

In the second example of the first embodiment, the first filter decision value is blocked based on the pixel values in line i = 3 and line i = 4 instead of line i = 2 and line i = 5. It is calculated as a filter decision value specific to. The corresponding lines i = 3 and i = 4 in the neighborhood block 20 are preferably used as a result to calculate the second filter decision value. The first filter decision value may then be calculated as | p2 ₃ -2p1 ₃ + p0 ₃ | + | p2 ₄ -2p1 ₄ + p0 ₄ |, where the second filter decision value is | q2 ₃ -2q1 ₃ + q0 ₃ | + | q2 ₄ -2q1 ₄ + q0 ₄ |, where p0 ₃ is the pixel of the pixel closest to block boundary 1 in the first line of pixels P1 ₃ represents the pixel value of the pixel that is second closest to the block boundary 1 in the first line of pixels, and p2 ₃ represents the value in the first line of pixels. in represents the pixel values of pixels that are close to the third block boundary 1, p0 ₄ is in the second line of pixels in the block 10, the pixels that are closest to the block boundary 1 It represents a pixel value, p1 ₄ from pixel That in the second line represents the pixel values of pixels that are close to the second block boundary 1, p2 ₄ is in the second line of pixels, close to the third block boundary 1 Q0 ₃ represents the pixel value of the pixel in the neighboring block 20 closest to the block boundary 1 in the corresponding first line of pixels, and q1 ₃ , within the first line corresponding of pixels represent pixel values of pixels around the block 20 in proximity to the second block boundary 1, q2 ₃ is a first line corresponding of pixels among represent pixel values of the pixels in neighboring blocks 20 which are close to the third block boundary 1, q0 ₄ is in the second line corresponding consisting pixels in neighboring blocks 20, block Neighboring block closest to boundary 1 Represents the pixel values of the pixels in 0, q1 ₄ is in the second line corresponding of pixels represent pixel values of pixels around the block 20 in proximity to the second block boundary 1, q2 ₄ represents the pixel value of the pixel in the neighboring block 20 that is third closest to the block boundary 1 in the corresponding second line of pixels.

  In the second embodiment, the first filter decision value and the second filter decision value are calculated for a group of four lines of pixels and four corresponding lines of pixels. This second embodiment may be appropriate when the blocks and neighboring blocks each have a size of 4 × 4 pixels. Furthermore, the second embodiment may be used for larger blocks of pixels such as 8x8 pixels. In the latter case, a filter decision pair is calculated for the first four line pixels and the first four corresponding lines of pixels, and another pair of filter decisions is the remaining four pixels. For the remaining four corresponding lines of pixels and pixels.

In the first example of the second embodiment, the first filter determination value is calculated as | p2 ₀ −2p1 ₀ + p0 ₀ | + | p2 ₃ −2p1 ₃ + p0 ₃ |, and | q2 ₀ −2q1 ₀ + q0 ₀ The second filter determination value is calculated as | + | q2 ₃ −2q1 ₃ + q0 ₃ |. In this case, the line consisting of pixels and the corresponding line consisting of pixels may continue from line number i = 0 to line number i = 3. For larger blocks of pixels such as i = 0-7 as shown in FIGS. 2A and 2B, the first pair of first filter decision value and second filter decision value is | p2 ₀ −2p1 ₀ + p0 ₀ | + | p2 ₃ −2p1 ₃ + p0 ₃ | and | q2 ₀ −2q1 ₀ + q0 ₀ | + | q2 ₃ −2q1 ₃ + q0 ₃ | This first pair of filter decision values is applicable to the first four lines of pixels and the first four corresponding lines of pixels, i = 0-3. The second pair of the first filter decision value and the second filter decision value results in | p2 ₄ -2p1 ₄ + p0 ₄ | + | p2 ₇ -2p1 ₇ + p0 ₇ | and | q2 ₄ -2q1 ₄ + q0 ₄ | + | q2 ₇ -2q1 ₇ + q0 ₇ | The second pair of filter decision values is consequently applicable to the four last lines of pixels and the four last corresponding lines of pixels, i = 4-7.

In the second example of the second embodiment, the first filter determination value is calculated as | p2 ₁ −2p1 ₁ + p0 ₁ | + | p2 ₂ −2p1 ₂ + p0 ₂ |, and | q2 ₁ −2q1 ₁ + q0 ₁ The second filter decision value is calculated as | + | q2 ₂ −2q1 ₂ + q0 ₂ |. In this case, the line consisting of pixels and the corresponding line consisting of pixels may continue from line number i = 0 to line number i = 3. For larger blocks of pixels such as i = 0-7 as shown in FIGS. 2A and 2B, the first pair of first filter decision value and second filter decision value is | p2 ₁ −2p1 ₁ + p0 ₁ | + | p2 ₂ −2p1 ₂ + p0 ₂ | and | q2 ₁ −2q1 ₁ + q0 ₁ | + | q2 ₂ −2q1 ₂ + q0 ₂ | This first pair of filter decision values is applicable to the first four lines of pixels and the first four corresponding lines of pixels, i = 0-3. The second pair of first and second filter decision values results in | p2 ₅ -2p1 ₅ + p0 ₅ | + | p2 ₆ -2p1 ₆ + p0 ₆ | and | q2 ₅ -2q1 ₅ + q0 ₅ | + | q2 ₆ -2q1 ₆ + q0 ₆ | The second pair of filter decision values is consequently applicable to the four last lines of pixels and the four last corresponding lines of pixels, i = 4-7.

This concept of the second embodiment is that the first filter decision value is calculated based on the pixel values of the pixels present in the subset of lines consisting of the pixels in the block, and the second filter decision value is calculated in the neighboring block. It can be extended if it is calculated based on the pixel values of the pixels present in the corresponding subset of lines of pixels. Thus, in this general concept of the second embodiment, the first filter decision value may be calculated as | p2 _i −2p1 _i + p0 _i | + | p2 _j −2p1 _j + p0 _j |. Here, i and j represent different line numbers in the sections 0 to N−1, and N represents the total number of lines composed of pixels in the block and neighboring blocks, where i ≠ j. The second filter decision value is therefore preferably calculated as | q2 _i −2q1 _i + q0 _i | + | q2 _j −2q1 _j + q0 _j |. This concept can, of course, be extended with a subset that stores three or more of the lines of pixels or the corresponding lines of pixels.

として計算され、第２のフィルタ決定値は、

として計算される。

は、異なるラインに固有の重みを表現する。この概念は、画素からなる３本以上のラインと画素からなる２本以上の対応するラインとを用いる場合にさらに拡張され得る。特有の例では、ブロック又は近傍ブロックの中央により近接している画素からなるライン又は画素からなる対応するラインは、その結果、ブロック又は近傍ブロックのエッジのうちの１つにより近接しているライン若しくは画素、又は、画素からなる対応するラインと比べるとかなり大きい重みが割り当てられる可能性がある。 In the related example of the first or third embodiment, the first filter determination value is

And the second filter decision value is

Is calculated as

Represents a unique weight for different lines. This concept can be further extended when using three or more lines of pixels and two or more corresponding lines of pixels. In a specific example, a line consisting of pixels closer to the center of a block or a neighboring block or a corresponding line consisting of pixels results in a line closer to one of the edges of the block or neighboring block or Significantly higher weights can be assigned compared to pixels or corresponding lines of pixels.

In the fourth embodiment, a combination of a filter determination value specific to a block and a filter determination value specific to a line should be filtered for a line made up of pixels in the block and a corresponding line made up of pixels in a neighboring block. Used to determine the number of pixels. FIG. 3 schematically illustrates such an embodiment. The method begins at step S10 where the third filter decision value is calculated as | p2 ₂ −2p1 ₂ + p0 ₂ | + | p2 ₅ −2p1 ₅ + p0 ₅ |, where p0 ₂ Represents the pixel value of the pixel closest to block boundary 1 in the second line of pixels, and p12 is the _second closest to block boundary 1 in the second line of pixels to and represents a pixel value of the pixel, p2 _2, within the second line of pixels represents the pixel values of pixels that are close to the third block boundary 1, p0 ₅ is block 10 Represents the pixel value of the pixel closest to the block boundary 1 in the third line of pixels, and p1 ₅ is second in the block boundary 1 in the third line of pixels. Represents the pixel value of adjacent pixels, _2-5, in the third line of pixels, representing pixel values of pixels that are close to the third block boundary 1. The second line of pixels preferably corresponds to line number 2 in the block 10 and the third line of pixels preferably corresponds to line number 5 in the block 10. See Figures 2A and 2B.

The next step S11 calculates the fourth filter decision value as | q2 ₂ −2q1 ₂ + q0 ₂ | + | q2 ₅ −2q1 ₅ + q0 ₅ |, where q0 ₂ is calculated from the pixels in the neighboring block 20. made in the corresponding second line represents the pixel values of the pixels in neighboring blocks 20 closest to the block boundary 1, q1 _2, within the second line corresponding of pixels, block represents a pixel value of a pixel around the block 20 in proximity to the second-boundary 1, q2 _2, within the second line corresponding of pixels, near in proximity to the third block boundary 1 The pixel value of the pixel in the block 20 is represented by q0 ₅ , the pixel of the pixel in the neighboring block 20 closest to the block boundary 1 in the corresponding third line composed of the pixels in the neighboring block 20. Represents a value , Q1 ₅ represent the pixel value of the pixel in the neighboring block 20 that is second closest to the block boundary 20 in the corresponding third line of pixels, and q2 ₅ represents the corresponding second line of pixels. Among the three lines, the pixel value of the pixel in the neighboring block 20 that is the third closest to the block boundary 1 is represented. The second corresponding line of pixels preferably corresponds to line number 2 in the neighboring block 20, and the third corresponding line of pixels preferably corresponds to line number 5 in the neighboring block 20. To do. See Figures 2A and 2B.

  Steps S10 and S11 can be performed in any order in series or at least partially in parallel.

In the next step S12, the third filter determination value calculated in step S10 is compared with the third threshold value (T ₃ ). If the third filter decision value is less than the third threshold value, the method continues to step S1 in FIG. 1 followed by step S3. Thus, in such a case, a unique or first filter decision value for each line is calculated for each line i in the block 10, where i is preferably from 0 to 7. . As a result, this first filter decision value is calculated as | p2 _i -2p1 _i + p0 _i | in step S1 of FIG. Step S3 in FIG. 1 is for the line i consisting of pixels in the block 10 to be filtered with respect to the block boundary 1 based on the first filter decision value calculated for the line i consisting of pixels in step S1. The number of pixels inside is determined. This procedure is executed for each line of pixels in the block 10. In this way, using the block 10 as shown in FIG. 2A or 2B, steps S1 and S3 are executed eight times. The method then continues to step S13 of FIG. Similarly, if the third filter decision value is not less than the third threshold in step S12, the method continues to step S13.

In step S13, the fourth filter determination value calculated in step S11 is compared with a _fourth threshold value (T ₄ ). If the fourth filter decision value is less than the fourth threshold, the method continues to steps S2 and S4 of FIG. A unique or second filter decision value for each line is calculated as | q2 _i -2q1 _i + q0 _i | for each corresponding line i in the neighborhood block 20 in step S2 of FIG. Step S4 in FIG. 3 consists of pixels in the neighboring block 20 to be filtered for block boundary 1 based on the second filter decision value calculated for the corresponding line i consisting of pixels in step S2. The number of pixels in the corresponding line i is determined. This procedure is executed for each corresponding line of pixels in the neighborhood block 20. The method then ends. Similarly, if the fourth filter decision value is not less than the fourth threshold in step S13, the method ends.

The loop formed by steps S12, S1 and S3 can be executed in any order sequentially or at least partially in parallel with the loop formed by steps S13, S2 and S4.

In the fourth embodiment example, a combination of block-based asymmetric filter determination and line-based asymmetric filter determination is used. In this example, the third filter decision value is calculated as d _p = | p2 ₂ -2p1 ₂ + p0 ₂ | + | p2 ₅ -2p1 ₅ + p0 ₅ |, and the fourth filter decision value is d _q = | q2 ₂ −2q1 ₂ + q0 ₂ | + | q2 ₅ −2q1 ₅ + q0 ₅ | The line specific filter decision values, i.e. the first and second filter decision values, are d _pi = | p2 _i -2p1 _i + p0 _i | and d _qi = | q2 for the line and the corresponding line number i, respectively. _i −2q1 _i + q0 _i |

● Calculate the _{d p,} to calculate the _{d q.}
If d _p <thr1,
○ For each line i (1) Calculate d _pi for line i.
When d _pi <thr1,
Perform standard filtering of the two pixels from line i in the current block 10, for example, the block border or boundary 1.
■ Otherwise, that is, when d _pi ≥ thr1
Do not filter the second pixel from the block border or boundary 1 of line i of current block 10 or do not filter the pixels on line i of current block 10 at all.
● Otherwise, that is, when d _p ≧ thr1,
O Do not filter the second pixel from the block border or boundary 1, or do not filter the pixel at all.
If d _q <thr2,
○ For each line i (1) Calculate d _qi for line i.
When d _qi <thr2,
Perform standard filtering of two pixels from a line i in the neighborhood block 20, for example, a block border or boundary 1.
■ Otherwise, that is, when d _qi ≧ thr2
Do not filter the second pixel from the block border or boundary 1 of line i of neighboring block 20 or do not filter the pixels on line i of neighboring block 20 at all.
If not, i.e. d _q ≥ thr2,
O Do not filter the second pixel from the block border or boundary 1, or do not filter the pixel at all.

  In the example disclosed above, the same threshold, ie thr1, is used when comparing the third filter decision value and the first filter decision value, and the fourth filter decision value and the second filter decision value. The same threshold, ie thr2, is used when comparing. In an alternative approach, the third threshold is used for the third filter decision value, the first threshold is used for the first filter decision value, and the fourth threshold is the fourth filter value. A second threshold is used for the decision value and a second threshold is used for the second filter decision value. In a specific embodiment, the third threshold and the fourth threshold are equal, and the first threshold and the second threshold are equal.

FIG. 4 is a flowchart showing a specific embodiment of the determination steps S3 and S4 of FIG. This method continues from step S2 in FIG. In the next step S20, the first filter determination value (d _p ) calculated in step S1 in FIG. 1 is compared with the first threshold value (T ₁ ). If the first filter decision value is less than the first threshold, the method continues from step S20 to step S21. In step S21, it is determined that two pixels in the line 12 including the pixels 11, 13, 15, and 17 in the block 10 are filtered with respect to the block boundary 1. These two pixels are preferably the second closest to the block 11 and the pixel 11 closest to the block boundary 1 in the line 12 comprising the pixels 11, 13, 15, 17. This is the pixel 13. However, if the first filter decision value is not less than the first threshold in step S20, the method instead continues to step S22. The first embodiment of step S22 determines to filter one pixel in the line 12 consisting of the pixels 11, 13, 15, 17 in the block 10 with respect to the block boundary 1. The pixel 11 is preferably the pixel 11 closest to the block boundary 1 in the line 12 including the pixels 11, 13, 15, and 17. The second embodiment of step S22 determines not to filter the pixels in the line 12 composed of the pixels 11, 13, 15, and 17 in the block 10 with respect to the block boundary 1.

Steps S <b> 23 to S <b> 25 execute a corresponding determination on the corresponding line 22 including the pixels 21, 23, 25, and 27 in the neighboring block 20. In this way, Step S23 compares the second filter determination value (d _q ) calculated in Step S2 of FIG. 1 with the second threshold value (T ₂ ). If the second filter decision value is less than the second threshold, the method continues to step S24. In step S24, it is determined that two pixels in the corresponding line 22 including the pixels 21, 23, 25, and 27 in the neighboring block 20 with respect to the block boundary 1 are to be filtered. These two pixels 21, 23 are preferably the pixel 21 closest to block boundary 1 and the second to block boundary 1 in the corresponding line 22 consisting of pixels 21, 23, 25. This is a pixel 23 close to. If the second filter decision value is not less than the second threshold, the method instead continues from step S23 to step S25. The first embodiment of step S25 determines to filter one pixel in the corresponding line 22 consisting of the pixels 21, 23, 25, 27 in the neighboring block 20 with respect to the block boundary 1. . This pixel 21 is preferably the pixel 21 closest to the block boundary 1 in the corresponding line 22 composed of the pixels 21, 23, 25, 27. The second embodiment of step S25 determines not to filter the pixels in the corresponding line 22 composed of the pixels 21, 23, 25, 27 in the neighboring block with respect to the block boundary 1.

  Steps S20, S21 and S22 may be performed before, after or at least partially in parallel with steps S23, S24 and S25.

This concept can be extended by using more than one threshold per filter decision value. For example, if d _p <T ₁ , two pixels are filtered in the line 12 consisting of the pixels 11, 13, 15, 17, and if T ₁ ≦ d _p <T ₁ ′, _one pixel Are filtered in the line 12 consisting of the pixels 11, 13, 15, 17 and if d _p ≧ T ₁ ′, the pixel is filtered in the line 12 consisting of the pixels 11, 13, 15, 17 Not processed. In this case, T ₁ <T ₁ ′. Similarly, when d _q <T ₂ , two pixels are filtered in the corresponding line 22 consisting of pixels 21, 23, 25, 27, and T ₂ ≦ d _q <T ₂ ′. If one pixel is filtered in the corresponding line 22 consisting of pixels 21, 23, 25, 27 and d _q ≧ T ₂ ′, the corresponding line consisting of pixels 21, 23, 25, 27 Pixels in 22 are not filtered. In this case, T ₂ <T ₂ ′.

  Thus, in a general aspect, the closer the first or second filter decision value is to zero, the more the first or second filter decision value is compared to the line of pixels or the corresponding line. By filtering and possibly modifying more pixels in it, more filtering should be applied to a specific line of pixels or a corresponding line. This means that a zero or small first or second filter decision value implies no or little structure, but rather implies a fairly uniform area within the video frame. Similarly, a large first or second filter decision value generally reflects a local structure within an area in the video frame, and this local structure should not be suppressed or filtered out.

  This embodiment reduces the computational complexity in the context of deblocking filtering because the filtering of the second pixel from the block border may not be performed as often as compared to the prior art HEVC solution. Decrease.

  The threshold described above and used to compare the various filter decision values preferably depends on the quantization parameter (QP) assigned to the block or neighboring block. FIG. 5 schematically illustrates such an approach. The method starts at step S30, where the first filter decision values are compared (see step S20 in FIG. 4) and the first threshold is determined based on the quantization parameter associated with block 10. Is done. Similarly, step S31 compares the second filter decision values based on the quantization parameter associated with the neighboring block 20 and / or the quantization parameter associated with the block 10 (step 23 in FIG. See: Determine second threshold.

For example, T ₁ and T ₂ are determined based on the parameter β determined from the QP value of the block 10 or the neighboring block 20. In a specific embodiment, the parameter β is read from the table based on the QP value. See Table 1 below.

In certain embodiments, T ₁ = T ₂ = β / 6 or T ₁ = T ₂ = (β + β >> 1) >> 3. As another variation of the embodiment, the threshold can be read from a separate table, ie T ₁ = function (QP), T ₂ = function (QP). Further, the third and fourth thresholds are preferably determined based on quantization parameters associated with the block and neighboring blocks, respectively.

FIG. 6 is a flow chart illustrating how the filtering control of the embodiment may be used in the context of a filtering process. The method starts at step S40, where the first offset or delta value Δ is (9 × (q0 _j −p0 _j ) −3 × (q1 _j −p1 _j )) / 16.
Where p0 _j represents the pixel value of the pixel 11 closest to the block boundary 1 in the line 12 consisting of pixels 11, 13, 15 and 17, and p1 _j is among the lines 12 of pixels 11, 13, 15, 17, represents the pixel value of the pixel 13 which is adjacent to the second block boundary 1, q0 _j the corresponding comprising pixels 21, 23 Represents the pixel value of the pixel 21 in the neighboring block 20 closest to the block boundary 1, and q1 _j is the corresponding line 22 composed of the pixels 21, 23, 25, and 27. , Represents the pixel value of the pixel 23 of the neighboring block 20 that is second closest to the block boundary 1.

This first offset is obtained by adding the first offset to the pixel value, i.e., p0 ′ _j = p0 _j + Δ, so that the block boundary 1 in the line 12 consisting of the pixels 11, 13, 15 and 17 is obtained. Used in step S41 to correct the pixel value of the closest pixel 11. In step S41, by subtracting the first offset from the pixel value, that is, q0 ′ _j = q0 _j −Δ, the block boundary 1 in the corresponding line 22 composed of the pixels 21, 23, 25, 27 is obtained. The pixel value of the closest pixel 21 is further corrected. The method then continues to steps S1 and S2 of FIG. 1 where a first filter decision value (d _p ) and a second filter decision value (d _q ) are calculated. The next step S42 compares the first filter decision value with the first threshold value (T ₁ ). This step S42 corresponds to step S20 in FIG. If the first filter decision value is less than the threshold, the method continues to step S43.

Step S43
(P0 _j + p2 _j -2p1 _j + 2Δ) / 4
To calculate a second offset or delta value Δ _p , where p 2 _j is third closest to block boundary 1 in line 12 consisting of pixels 11, 13, 15, 17. The pixel value of the pixel 15 is represented. The second offset is then obtained by adding the second offset to the pixel value, i.e., p1 ′ _j = p1 _j + _Δp , so that the block boundary within the line 12 consisting of pixels 11, 13, 15, 17 Used in step S44 to modify the pixel value of the pixel 13 that is second closest to 1.

  The method then continues to step S45. This method continues similarly from step S42 to step S45 in FIG. 6 if the first filter decision value is not less than the first threshold.

A step S45 compares the second filter decision value with the second threshold value (T ₂ ). This step S45 corresponds to step S23 in FIG. If the second filter decision value is less than the second threshold, the method continues to step S46. Step S46
_{(Q0 j + q2 j -2q1 j} -2Δ) / 4
To calculate a third offset Δ _q , where _{q 2 j} is the neighborhood closest to block boundary 1 in the corresponding line 22 consisting of pixels 21, 23, 25, 27. The pixel value of the pixel 25 in the block 20 is represented. Third offset by adding the third offset to the pixel value, i.e., by _{q1 'j = q1 j + Δ} q, in the corresponding line 22 of pixels 21, 23, block Used in step S47 to modify the pixel value of pixel 23 that is second closest to boundary 1.

  Steps S42, S43 and S44 may be performed in any order in series or at least partially in parallel with steps S45, S46 and S47.

In the above, the first, second and third offsets are calculated based on a specific equation for pixel values. This is because the first offset is (9 × (q0 _j −p0 _j ) −3 × (q1 _j −p1 _j )) / 16
And the second offset is (p0 _j + p2 _j -2p1 _j + 2Δ) / 4
And the third offset is (q0 _j + q2 _j -2q1 _j -2Δ) / 4
It is calculated as a function of. Various such functions are conceivable and can be used in steps S40, S43 and S46. Such a function can therefore be defined so that the calculation of the offset is performed efficiently in hardware. In such cases, it is generally preferred not to include division and / or not define the function such that the offset is an integer value. In an embodiment, (X + 8) >> 4 is used as an integer representation of X / 16, where >> represents a right shift operation. Thus, in certain embodiments, step S40 is
(9 × (q0 _j −p0 _j ) −3 × (q1 _j −p1 _j ) +8) >> 4
And, preferably, the first offset is calculated to match. The corresponding integer representation of the second and third offsets is
(((P0 _j + p2 _j +1) >> 1) −p1 _j + Δ) >> 1
And _{(((q0 j + q2 j} +1) >> 1) -q1 j -Δ) >> 1
It can be.

As an example, pixel values modified as a result of deblocking are calculated as follows: In this example, the first filter decision value is defined as d _p = | p2 ₂ -2p1 ₂ + p0 ₂ | + | p2 ₅ -2p1 ₅ + p0 ₅ |, and the second filter decision value is d _q = | q2 ₂ −2q1 ₂ + q0 ₂ | + | q2 ₅ −2q1 ₅ + q0 ₅ |

Δ = (9 × (q0−p0) −3 × (q1−p1)) / 16
● p ′ ₀ = p ₀ + Δ
Q ′ ₀ = q ₀ −Δ
If d _p <thrP,
○ Δ _p = (p0 + p2-2p1 + 2Δ) / 4
○ p ′ ₁ = p ₁ + Δ _p
If d _q <thrQ,
○ Δ _q = (q0 + q2-2q1-2Δ) / 4
○ q ′ ₁ = q ₁ + Δ _q

The exact formula for the above example calculation in a programming language may look like the following text: Here, the Clip3 function is a clipping of the output value to the range between the two first function arguments.

Int xCalcDP (Pel * piSrc, Int iOffset)
{
return abs (piSrc [-iOffset * 3] -2 * piSrc [-iOffset * 2] + piSrc [-iOffset]);
}

Int xCalcDQ (Pel * piSrc, Int iOffset)
{
return abs (piSrc [0] -2 * piSrc [iOffset] + piSrc [iOffset * 2]);
}

Int iDP = xCalcDP (piTmpSrc + iSrcstep * (iIdx * uiPelsInPart + iBlkIdx * DEBLOCK_SMALLEST_BLOCK + 2), iOffset) + xCalcDP (piTmpSrc + iSrcStep * (iIdx * uiPelsInpart + iBlkIdx * DEBLOCK_SMALLEST_BLOCK + 5), iOffset);

Int iDQ = xCalcDQ (piTmpSrc + iSrcstep * (iIdx * uiPelsInPart + iBlkIdx * DEBLOCK_SMALLEST_BLOCK + 2), iOffset) + xCalcDQ (piTmpSrc + iSrcStep * (iIdx * uiPelsInpart + iBlkIdx * DEBLOCK_SMALLEST_BLOCK + 5), iOffset);

Int iSideThreshold = iBeta / 6;

Bool bFilterP = (iDP <iSideThreshold);
Bool bFilterQ = (iDQ <iSideThreshold);

delta = (9 * (m4-m3) -3 * (m5-m2) +8) >>4;

if (abs (delta) <iThrCut)
{
Int tc2 = tc >>1;

delta = Clip3 (−tc, tc, delta);
piSrc [-iOffset] = Clip ((m3 + delta));
piSrc [0] = Clip ((m4-delta));

if (bFilterP)
{
Int delta1 = Clip3 (−tc2, tc2, ((((m1 + m3 + 1) >> 1) −m2 + delta) >>1));
piSrc [-iOffset * 2] = Clip ((m2 + delta1));
}
if (bFilterQ)
{
{
Int delta2 = Clip3 (−tc2, tc2, ((((m6 + m4 + 1) >> 1) −m5-delta) >>1));
piSrc [iOffset * 2] = Clip ((m5 + delta2));
}
}

  FIG. 7 is a flowchart illustrating additional selectable steps of the method in FIG. This method continues from step S2 in FIG. The next step S50 compares the sum of the first determined value and the second determined value with a threshold value (T). If the sum is not less than the threshold, the method ends. Thus, in such a case, no filtering is applied to block 10 and neighboring block 20 with respect to the specific block boundary 1. Block 10 and neighboring block 20 consequently comprise a number of local structures that should not be filtered out. However, if the sum is less than the threshold, the method continues with steps S3 and S4 in FIG. 1, where the determination of the number of pixels to be filtered is determined by the first filter decision value (step S3) or the second. This is executed based on the determined filter value (step S4).

  This embodiment has the advantage that it does not require a lot of additional computation since the values for the first and second filter decisions are further used to determine if any block boundaries should be filtered. Have.

  The embodiments disclosed herein implement asymmetric deblocking decisions that control deblocking filtering to accommodate the structure on both sides of the block boundary. The asymmetry determination allows the amount of filtering applied to one side of the block boundary to be different from the amount of filtering applied to the other side of the block boundary, thus making further adaptation to the local structure Means. This improves objective and subjective video quality.

FIG. 8 is a schematic block diagram of an embodiment of the filtering control apparatus 100. The filtering controller 100 includes a first decision value calculator 110 configured to calculate a first filter decision value for the block 10 in the video frame based at least on | p2 _i -2p1 _i + p0 _i |. Prepare. The filtering controller 100 further comprises a second decision value calculator 120 configured to calculate a second different filter decision value for the block 10 based on | q2 _i -2q1 _i + q0 _i |.

  The first pixel decision unit 130 or the first pixel decision unit or processor should filter the block boundary 1 based on the first filter decision value calculated by the first decision value calculator 110 The number of pixels in the line 12 composed of the pixels 11, 13, 15, and 17 in the block 10 is determined. The second pixel determination unit 140 or the second pixel determination unit or processor uses the second filter determination value calculated by the second determination value calculator 120 to perform an image to be filtered with respect to the block boundary. The filtering control device 100 is provided to determine the number of pixels in the corresponding line 22 composed of the pixels 21, 23, 25, and 27 in the neighborhood block 20 of the frame.

  In the embodiment, the first pixel determination unit 130 is based on the first filter determination value calculated by the first determination value calculator 110 for the first line 12 including the pixels 11, 13, 15, and 17. Thus, the number of pixels in the first line 12 made up of the pixels 11, 13, 15, and 17 in the block 10 to be filtered with respect to the block boundary 1 is determined. The second pixel determination unit 140 is based on the second filter determination value calculated by the second determination value calculator 120 for the corresponding first line 22 including the pixels 21, 23, 25, and 27. The number of pixels in the corresponding first line 22 composed of the pixels 21, 23, 25, 27 in the neighboring block 20 to be filtered with respect to the block boundary 1 is similarly determined.

In another embodiment, the first decision value calculator 110 is configured to calculate the first filter decision value as | p2 ₂ −2p1 ₂ + p0 ₂ | + | p2 ₅ −2p1 ₅ + p0 ₅ | The second determined value calculator 120 is configured to calculate the second filter determined value as | q2 ₂ −2q1 ₂ + q0 ₂ | + | q2 ₅ −2q1 ₅ + q0 ₅ |.

In yet another embodiment, the first decision value calculator 110 uses the first filter decision value in the first pair as | p2 ₀ -2p1 ₀ + p0 ₀ | + | p2 ₃ -2p1 ₃ + p0 ₃ |. And the second decision value calculator 120 determines the second filter decision in the first pair as | q2 ₀ -2q1 ₀ + q0 ₀ | + | q2 ₃ -2q1 ₃ + q0 ₃ | Configured to calculate a value. The first filter decision value calculator 110 is further configured to calculate the first filter decision value in the second pair as | p2 ₄ −2p1 ₄ + p0 ₄ | + | p2 ₇ −2p1 ₇ + p0 ₇ |. Configured, the second filter decision value calculator 120 calculates the second filter decision value in the second pair as | q2 ₄ −2q1 ₄ + q0 ₄ | + | q2 ₇ −2q1 ₇ + q0 ₇ | It is further configured as follows.

FIG. 9 is a schematic block diagram of another embodiment of the filtering control apparatus 100. In the present embodiment, the filtering control apparatus 100 includes, in addition to the first determined value calculator 110, a second determined value calculator 120, a first pixel determiner 130, and a second pixel determiner 140. And a third determined value calculator 150. As a result, the third decision value calculator 150 is configured to calculate the third filter decision value as | p2 ₂ −2p1 ₂ + p0 ₂ | + | p2 ₅ −2p1 ₅ + p0 ₅ |. The fourth decision value calculator 160 is further implemented in the filtering control apparatus 100 so as to calculate the fourth filter decision value as | q2 ₂ −2q1 ₂ + q0 ₂ | + | q2 ₅ −2q1 ₅ + q0 ₅ |. It is configured.

In the present embodiment, the first filter decision value calculator 110, when the third filter decision value calculated by the third decision value calculator 150 is less than the third threshold value, Is configured to calculate If the third decision value is less than the third threshold, the first decision value calculator 110 sets each of the pixels 11, 13, 15, and 17 in the block 10 as | p2 _i -2p1 _i + p0 _i |. Calculate a first threshold for line i12. Thereafter, the first pixel determination unit 130 determines whether or not the third filter determination value is less than the third threshold value, and determines whether the pixel i for each line i 12 including the pixels 11, 13, 15, and 17 in the block 10. Based on the first filter decision value calculated by the first decision value calculator 110 for the line i 12 consisting of 11, 13, 15, 17 in the block 10 to be filtered with respect to the block boundary 1 The number of pixels in the line i 12 composed of the pixels 11, 13, 15, and 17 is determined.

The second determined value calculator 120 is preferably responsive to the comparison between the fourth filter determined value and the fourth threshold. Thus, when the fourth filter decision value calculated by the fourth decision value calculator 160 is less than the fourth threshold value, the second decision value calculator 120 determines whether the pixel 21 in the neighboring block 20, For each corresponding line i 22 consisting of 23, 25, 27, the second filter decision value is calculated as | q2 _i -2q1 _i + q0 _i |. The second pixel determination unit 240 determines whether or not the fourth filter determination value is less than the fourth threshold value, and for each corresponding line i 22 composed of the pixels 21, 23, 25, and 27 in the neighboring block 20. Based on the second filter decision value calculated for the corresponding line i 22 consisting of pixels 21, 23, 25, 27, the pixels 21, 23, The number of pixels in the corresponding line i 22 consisting of 25 and 27 is determined.

  FIG. 10 is a schematic block diagram of a further embodiment of the filtering control apparatus 100. In addition to the units 110-140 of the embodiment shown in FIG. 8, the filter rig control device 100 compares the first filter decision value calculated by the first decision value calculator 110 with a first threshold value. The first comparator 180 is configured as described above. The second comparator 182 is similarly configured to compare the second filter decision value calculated by the second decision value calculator 120 with a second threshold value.

  In the present embodiment, the first pixel determiner 130 determines that the block 10 for the block boundary 1 when the first filter decision value is less than the first threshold as determined by the first comparator 180. It is configured to determine that two pixels in the line 12 including the pixels 11, 13, 15, and 17 are to be filtered. However, if the first filter decision value is not less than the first threshold, the first pixel determiner 130 instead consists of the pixels 11, 13, 15, 17 in the block 10 with respect to the block boundary 1 It is configured to determine to filter one pixel in line 12. Alternatively, the first pixel determiner 130 instead determines not to filter the pixels in the line 12 consisting of the pixels 11, 13, 15, 17 in the block 10 with respect to the block boundary 1. It is configured as follows.

  The second pixel determination unit 140 determines that the pixel 21 in the neighboring block 20 with respect to the block boundary 1 when the second filter determination value is less than the second threshold as determined by the second comparator 182. , 23, 25, 27 are configured to determine to filter two pixels in the corresponding line 22. However, if the second filter decision value is not less than the second threshold value, the second pixel determination unit 140 instead uses the pixels 21, 23, 25, and 27 in the neighboring block 20 with respect to the block boundary 1. Is configured to determine to filter one pixel in the corresponding line 22. Alternatively, the second pixel determiner 140 instead does not filter the pixels in the corresponding line 22 consisting of the pixels 21, 23, 25, 27 in the neighboring block 20 with respect to the block boundary 1. Is configured to determine.

In the embodiment, the filtering control apparatus 100 of FIG.
(9 × (q0 _j −p0 _j ) −3 × (q1 _j −p1 _j )) / 16
A first offset calculator 181 configured to calculate a first offset based on The first pixel corrector 190 of the filtering control device 100 adds the first offset to the pixel value of the pixel 11, and thereby the block boundary 1 in the line 12 including the pixels 11, 13, 15, and 17 is added. The pixel value of the closest pixel 11 is configured to be corrected. The second pixel value corrector 192 subtracts the first offset from the pixel value of the pixel 21 so that it is closest to the block boundary 1 in the corresponding line 12 consisting of the pixels 21, 23, 25, 27. The pixel value of the pixel 21 is modified.

The second offset calculator 183 is preferably filtered to calculate a second offset if the first filter decision value is less than the first threshold as determined by the first comparator 180. It is mounted on the control device 100. The second offset is then
(P0 _j + p2 _j -2p1 _j + 2Δ) / 4
Calculated based on The third pixel modifier 194 is activated when the first filter decision value is less than the first threshold. In such a case, the third pixel corrector 194 adds the second offset to the pixel value of the pixel 13 so that the line boundary 12 in the pixel 11, 13, 15, and 17 becomes the block boundary 1. The pixel value of the pixel 13 closest to the second pixel is corrected.

The third offset calculator 185 is when the second filter decision value is less than the second threshold as determined by the second comparator 182;
_{(Q0 j + q2 j -2q1 j} -2Δ) / 4
Is configured to calculate a third offset based on. When the second filter determination value is less than the second threshold value, the fourth pixel corrector 196 of the filtering control apparatus 100 adds the third offset to the pixel value of the pixel 23, whereby the pixels 21, 23 are added. , 25 and 27, the pixel value of the pixel 23 that is second closest to the block boundary 1 is corrected.

  The embodiment of the filtering control apparatus 100 described above in connection with FIGS. 9 and 10 compares the filter decision values with respective threshold values. In an embodiment, such a threshold is calculated by the filtering controller 100 for the specific block boundary 1. The filtering controller 100 therefore preferably uses the first threshold used by the first comparator 180 in FIG. 10 and the filtering controller 100 in FIG. 9 based on the quantization parameter associated with the block 10. Comprises a threshold determiner 170 or a threshold determination processor or unit configured to determine a third threshold used by. Similarly, threshold determiner 170 preferably also uses the second threshold used by second comparator 182 in FIG. 10 based on the quantization parameter associated with neighboring block 20, and in FIG. The fourth threshold value used by the filtering control device 100 is determined.

  FIG. 11 is a schematic block diagram of still another embodiment of the filtering control apparatus 100. In addition to the units 110 to 140 of the embodiment shown in FIG. 8, the filtering control apparatus 100 in this embodiment is configured to compare the sum of the first filter determination value and the second filter determination value with a threshold value. Is provided with a third comparator 184. If this sum is greater than or equal to the threshold, the first and second pixel determiners 130, 140 filter because the filtering should not be applied to the block 10 and the neighboring block 20 with respect to the specific block boundary 1. It will not determine any number of power pixels. However, if the sum is less than the threshold value, the first and second pixel determiners 130 and 140 operate to determine the number of pixels to be filtered based on the first or second filter decision value, respectively. Is done.

  The embodiments of the filtering control device 100 previously described and disclosed in FIGS. 8-11 may be combined. For example, the third value calculator 150 and the fourth value calculator 160 of FIG. 9 may be implemented in any of the embodiments disclosed in FIG. Similarly, the third comparator 184 of FIG. 11 may be implemented in any of the embodiments disclosed in FIG. 9 or 10.

  Each of the units 110-196 disclosed in connection with FIGS. 8-11 are disclosed as physically separate units 110-196 in the filtering controller 100, but all are ASIC (application specific integrated circuits). An alternative embodiment of the filtering controller 100 is conceivable in which some or all of the units 110-196 are implemented as computer program modules that run on a general purpose processor. Such an embodiment is disclosed in FIG.

  FIG. 12 schematically illustrates an embodiment of a computer 70 having a processing unit 72 such as a DSP (Digital Signal Processor) or CPU (Central Processing Unit). The processing unit 72 may be a single unit or multiple units that perform the various steps of the methods described herein. The computer 70 further includes an input / output (I / O) unit 71 that receives the recorded or generated video frame or the encoded video frame and outputs the encoded video frame or the decoded video data. . Although the I / O unit 71 is shown as a single unit in FIG. 12, it may likewise be in the form of a separate input unit and a separate output unit.

  Furthermore, the computer 70 comprises at least one computer program product 73 in the form of a non-volatile memory such as, for example, an EEPROM (electrically erasable programmable read only memory), a flash memory, or a disk drive. . The computer program product 73 comprises a computer means comprising code means that, when run or executed by a computer 70, such as the processing unit 72, causes the computer 70 to perform the steps of the method described above in connection with FIG. 74. Accordingly, in an embodiment, the code means in the computer program 74 includes a first decision value calculation (DVC) module 310 for calculating a first filter decision value for the block and a second filter decision value for the block. 2 pixel value calculation module 320, first pixel determination (PD) module 330 that determines the number of pixels to be filtered in line 12 consisting of pixels 11, 13, 15, and 17, and pixels 21 and 23 , 25, 27, and a second pixel determination module 340 that determines the number of pixels to be filtered in the corresponding line 22. These modules 310-340, in principle, perform the steps of the flowchart of FIG. In this way, when the various modules 310-340 are moved on the processing unit 72, these correspond to the corresponding units 110-140 of FIGS.

  The computer program 74 performs a third decision value calculation module, a fourth decision value calculation module, a threshold determination module, a first comparison module, in order to execute the operations of the corresponding units 150 to 196 in FIGS. A second comparison module, a third comparison module, a first offset calculation module, a second offset calculation module, a third offset calculation module, a first pixel correction module, a second pixel correction module, and a third The pixel correction module and / or the fourth pixel correction module may be further included.

  The computer 70 of FIG. 12 may be user equipment or may exist in the user equipment. In such a case, the user equipment may further include or be connected to a display that displays video data.

  The filtering control devices of FIGS. 8 to 11 are preferably used in video coding. This works and, as a result, is preferably implemented in both the video encoder and video decoder. The video decoder is preferably implemented in hardware, but may also be implemented in software. The same is true for the video encoder.

  FIG. 13 is a schematic block diagram of an encoder 40 that encodes a block of pixels in a video frame of a video sequence according to the embodiment.

  A current block of pixels is predicted by performing motion estimation by the motion estimator 50 from a block of already supplied pixels in the same frame or previous frame. The result of motion estimation is the motion or displacement vector associated with the reference block in the case of inter prediction. The motion vector is used by a motion compensator 50 that outputs inter prediction of a block of pixels.

  The intra predictor 49 calculates the intra prediction for the current block of pixels. The outputs from the motion estimator / compensator 50 and the intra predictor 49 are input to a selector 51 that selects either intra prediction or inter prediction for the current block of pixels. The output from the selector 51 is input to an error calculator in the form of an adder 41 that further receives the pixel values of the current block of pixels. The adder 41 calculates and outputs a residual error as a difference in pixel value between the block composed of pixels and the prediction thereof.

  The error is converted by the converter 42 by discrete cosine transform or the like, quantized by the quantizer 43, and subsequently encoded by the encoder 44 by an entropy encoder or the like. In inter-coding, similarly estimated motion vectors are fed into an encoder 44 that generates an encoded representation of the current block of pixels.

  The transformed and quantized residual error for the current block of pixels is further supplied to an inverse quantizer 45 and an inverse transformer 46 to extract the original residual error. This error is added to the block prediction output from motion compensator 50 or to intra prediction 49 to create a reference block of pixels that can be used to predict and encode the next block of pixels. 47 is added. This new reference block is first processed by the filtering controller 100 according to the embodiment to control any deblocking filtering applied to the reference block to reduce blocking artifacts. The processed new reference block is then temporarily stored in the frame buffer 48, and the new reference block is available from the intra predictor 49 and motion estimator / compensator 50 in this frame buffer.

  FIG. 14 is a corresponding schematic block diagram of a decoder 60 comprising a filtering control device 100 according to an embodiment. The decoder 60 comprises a decoder 61, such as an entropy decoder, that decodes an encoded representation of a block of pixels to obtain a transformed and quantized residual error set. These residual errors are inversely quantized by the inverse quantizer 62 and inversely transformed by the inverse transformer 63 in order to obtain a set of residual errors.

  These residual errors are added in the adder 64 to the pixel value of the reference block made up of pixels. The reference block is determined by the motion estimator / compensator 67 or the intra predictor 66 depending on whether inter prediction is performed or intra prediction is performed. Selector 68 is thereby interconnected to summer 64 and motion estimator / compensator 67 and intra predictor 66. The resulting block of decoded pixels output from adder 64 is input to filtering controller 100 according to an embodiment to control any deblocking filter applied to reduce blocking artifacts. Is done. A block of filtered pixels is output from the decoder 60 and more preferably temporarily supplied to the frame buffer 65 and used as a reference block of pixels for the subsequent block of pixels to be decoded. Can be done. The frame buffer 65 is thereby connected to the motion estimator / compensator 67 to make a block of stored pixels available to the motion estimator / compensator 67.

  The output from adder 64 is also preferably input to intra predictor 66 for use as a reference block of unfiltered pixels.

  In the embodiment disclosed in FIGS. 13 and 14, the filtering control apparatus 100 controls deblocking filtering in the form of so-called in-loop filtering. In an alternative implementation at the decoder 60, the filtering control device 100 is arranged to perform so-called post-processing filtering. In such a case, the filtering controller 100 operates the output frame outside the loop formed by the adder 64, the frame buffer 65, the intra predictor 66, the motion estimator / compensator 67, and the selector 68. As a result, filtering and filtering control without deblocking is typically performed at the encoder.

  FIG. 15 is a schematic block diagram of a user equipment or media terminal 80 that houses a decoder 60 with a filter control device. User equipment 80 may be any device having a media decoding function that manipulates the encoded video stream of the encoded video frames, thereby decoding the video frames and making the video data available. Non-limiting examples of such devices include mobile phones and other portable media players, tablets, desktops, notebooks, personal video recorders, multimedia players, video streaming servers, set top boxes, TVs Computer, decoder, game console, etc. User equipment 80 includes a memory 84 configured to store encoded video frames. These encoded video frames may have been generated by the user equipment 80 itself. Alternatively, the encoded video frame is generated by another device and transmitted to the user equipment 80 by wireless transmission or wired transmission. As a result, the user equipment 80 includes transceivers (transmitters and receivers) or input / output ports 82 to implement data transfer.

  The encoded video frame is carried from the memory 84 to a decoder 60 such as the decoder shown in FIG. The decoder 60 includes the filtering control device 100 according to the embodiment. As a result, the decoder 60 decodes the encoded video frame into a decoded video frame. The decoded video frame is a medium configured to turn the decoded video frame into a video data representation that can be displayed on the user device 80 or a display or screen 88 connected to the user device 80. Supplied to the player 86.

  In FIG. 15, user equipment 80 includes both a decoder 60 and a media player 86, and the decoder 60 is shown as being implemented as part of the media player 86. However, this is merely an example of an implementation for user equipment 80 and should be taken as a non-limiting example. Further, a distributed implementation is contemplated in which the decoder 60 and media player 86 are provided in two physically separate devices and are within the scope of the user equipment 80 as used herein. Display 88 may be similarly provided as a separate device connected to user equipment 80 where actual data processing is performed.

  FIG. 16 shows another embodiment of user equipment 80 that provides an encoder with a filtering controller according to an embodiment, such as the encoder of FIG. Encoder 40 is thus configured to encode video frames received by I / O unit 82 and / or generated by user equipment 80 itself. In the latter case, the user equipment 80 preferably comprises a media engine or recorder, for example in the form of a (video) camera or connected to a (video) camera. The user equipment 80 may further comprise a media player 86, such as a media player 86 with a decoder and filtering controller according to embodiments, and a display 88, as the case may be.

  As shown in FIG. 17, an encoder 40 and / or decoder 60 as shown in FIGS. 13 and 14 is a network node in the communication network 32 between the transmitting unit 34 and the receiving user equipment 36. It may be implemented by a network device 30 that is or belongs to a network node. Such a network device 30 has, for example, only the capability of another video coding standard, not the video coding standard transmitted by the transmission unit 34, by the receiving user equipment 36, or another video coding standard. In the case where priority is established, an apparatus for converting a video according to one video coding standard into another video coding standard may be used. The network device 30 may be in the form of or included in a radio base station, Node-B, or any other network node in a communication network 32 such as a radio base network. is there.

  The foregoing embodiments are to be understood as some illustrations of the invention. It will be appreciated by those skilled in the art that various modifications, combinations and changes may be made to the embodiments without departing from the scope of the invention. Specifically, the various partial solutions in the various embodiments can be combined with other configurations where technically possible. However, the scope of the invention is defined by the claims.

Claims (15)

A filtering control method applicable to a block (10) comprising a plurality of pixels (11, 13, 15, 17) in a video frame in which each pixel (11, 13, 15, 17) has a respective pixel value. ,
p0 _i is a plurality of pixels (21, 23, 25, 27) in the video frame in the first line (12) consisting of pixels (11, 13, 15, 17) in the block (10). Represents the pixel value of the pixel (11) closest to the block boundary (1) to the neighboring block (20) consisting of the first line, where p1 _i is composed of the pixels (11, 13, 15, 17) In (12), the pixel value of the pixel (13) that is second closest to the block boundary (1) is represented, and p2 _i is composed of the pixels (11, 13, 15, 17). If the pixel value of the pixel (15) third closest to the block boundary (1) in the line (12) is represented,
| P2 _i -2p1 _i + p0 _i |
(S1) calculating a first filter decision value for the block (10) using only the pixel values p2 _i , p1 _i , and p0 _i based on
The neighborhood where q0 _i is closest to the block boundary (1) in the corresponding first line (22) consisting of the pixels (21, 23, 25, 27) in the neighborhood block (20) The pixel value of the pixel (21) in the block (20) is represented, and q1 _i is the block boundary (1) in the corresponding first line (22) including the pixels (21, 23, 25, 27). ) Represents the pixel value of the pixel (23) of the neighboring block (20) that is second closest, and q2 _i is the corresponding first line (22) consisting of the pixels (21, 23, 25, 27). ) Represents the pixel value of the pixel (25) in the neighboring block (20) that is third closest to the block boundary (1).
| Q2 _i -2q1 _i + q0 _i |
(S2) calculating a second filter decision value for the neighboring block (20) using only the pixel values q2 _i , q1 _i , and q0 _i based on
Pixels (11, 13, 15, 17) in the block (10) to be filtered with respect to the block boundary (1) based on the comparison (S20) between the first filter decision value and the first threshold value Determining (S3) the number of pixels in the first line (12) comprising:
The pixels (21, 23, 25, 27 in the neighboring block (20) to be filtered with respect to the block boundary (1) based on the comparison between the second filter decision value and the second threshold value (S23). A step (S4) of determining the number of pixels in the corresponding first line (22) consisting of:
Equipped with a,
The step (S1) of calculating the first filter determination value includes the pixel of the pixel closest to the block boundary (1) in the first line in which p0 ₀ is composed of a plurality of pixels. P1 ₀ represents the pixel value of the pixel second closest to the block boundary (1) in the first line composed of a plurality of pixels, and p2 ₀ represents a plurality of pixels Represents the pixel value of the pixel that is third closest to the block boundary (1) in the first line consisting of: p0 ₃ is the number of pixels in the block (10). 2 represents the pixel value of the pixel closest to the block boundary (1), and p1 ₃ represents the block boundary (1) in the second line composed of a plurality of pixels. Represents the pixel value of the second closest pixel, p ₃ is in the second line comprising a plurality of pixels, when representing pixel values of pixels that are close to the third to the block boundary (1),
| P2 ₀ -2p1 ₀ + p0 ₀ | + | p2 ₃ -2p1 ₃ + p0 ₃ |
A step (S1) of calculating the first filter decision value as
The step (S2) of calculating the second filter decision value includes the neighboring block closest to the block boundary (1) in the corresponding first line in which q0 ₀ is composed of a plurality of pixels. represents the pixel value of the pixel in the (20), q1 ₀ is in the first line of the corresponding a plurality of pixels, the neighboring block which is close to the second to the block boundary (1) represents the pixel value of the pixel of (20), q2 ₀ is in the first line of the corresponding a plurality of pixels, said block the neighboring blocks in proximity to the third to the boundary (1) ( represents the pixel value of the pixel in the 20), in the second line corresponding q0 ₃ consists of a plurality of pixels of the neighboring blocks (20), closest to the block boundary (1) The neighboring block (2 0) represents the pixel values of the pixels in, q1 ₃ is in the second line the corresponding a plurality of pixels, said block boundary (1) to the neighboring blocks in proximity to the second (20) The pixel in the neighboring block (20) that is third closest to the block boundary (1) in the corresponding second line consisting of a plurality of pixels is represented by the pixel value of q2 ₃ If the pixel value of
| Q2 ₀ -2q1 ₀ + q0 ₀ | + | q2 ₃ -2q1 ₃ + q0 ₃ |
A step (S2) of calculating the second filter decision value as
METHODS. The step (S3) of determining the number of pixels in the first line (12) consisting of the pixels (11, 13, 15, 17) in the block (10) to be filtered,
Comparing the first filter decision value with a first threshold value (S20);
If the first filter decision value is less than the first threshold, the first filter comprising pixels (11, 13, 15, 17) in the block (10) with respect to the block boundary (1) Determining to filter two pixels in line (12) (S21);
When the first filter determination value is greater than or equal to the first threshold value, the first filter comprising the pixels (11, 13, 15, 17) in the block (10) with respect to the block boundary (1) Determining (S22) to filter one pixel in the line (12);
With
The step (S4) of determining the number of pixels in the corresponding first line (22) consisting of the pixels (21, 23, 25, 27) in the neighboring block (20) to be filtered,
Comparing the second filter decision value with a second threshold value (S23);
If the second filter decision value is less than the second threshold, the corresponding consisting of pixels (21, 23, 25, 27) in the neighboring block (20) with respect to the block boundary (1) Determining to filter two pixels in the first line (22) (S24);
If the second filter decision value is greater than or equal to the second threshold, the corresponding consisting of pixels (21, 23, 25, 27) in the neighboring block (20) with respect to the block boundary (1) Determining to filter one pixel in the first line (22) (S25);
The method of claim 1, comprising : The step (S3) of determining the number of pixels in the first line (12) consisting of the pixels (11, 13, 15, 17) in the block (10) to be filtered,
Comparing the first filter decision value with a first threshold value (S20);
If the first filter decision value is less than the first threshold, the first filter comprising pixels (11, 13, 15, 17) in the block (10) with respect to the block boundary (1) Determining to filter two pixels in line (12) (S21);
When the first filter determination value is greater than or equal to the first threshold value, the first filter comprising the pixels (11, 13, 15, 17) in the block (10) with respect to the block boundary (1) Determining not to filter the pixels in line (12) (S22);
With
The step (S4) of determining the number of pixels in the corresponding first line (22) consisting of the pixels (21, 23, 25, 27) in the neighboring block (20) to be filtered,
Comparing the second filter decision value with a second threshold value (S23);
If the second filter decision value is less than the second threshold, the corresponding consisting of pixels (21, 23, 25, 27) in the neighboring block (20) with respect to the block boundary (1) Determining to filter two pixels in the first line (22) (S24);
If the second filter decision value is greater than or equal to the second threshold, the corresponding consisting of pixels (21, 23, 25, 27) in the neighboring block (20) with respect to the block boundary (1) Determining (S25) not to filter the pixels in the first line (22);
The method of claim 1, comprising : In a first line (12) consisting of pixels (11, 13, 15, 17) in a block (10) consisting of a plurality of pixels (11, 13, 15, 17) in a video frame, p0 _i The pixel value of the pixel (11) closest to the block boundary (1) to the neighboring block (20) composed of a plurality of pixels (21, 23, 25, 27) in the video frame is represented, and p1 _i is Represents the pixel value of the pixel (13) second closest to the block boundary (1) in the first line (12) consisting of pixels (11, 13, 15, 17), and p2 _i Represents the pixel value of the pixel (15) third closest to the block boundary (1) in the first line (12) composed of pixels (11, 13, 15, 17). ,
| P2 _i -2p1 _i + p0 _i |
Based on a first decision value calculator configured to calculate a first filter decision value for the block (10) using only the pixel values p2 _i , p1 _i , and p0 _i 110)
The neighborhood where q0 _i is closest to the block boundary (1) in the corresponding first line (22) consisting of the pixels (21, 23, 25, 27) in the neighborhood block (20) The pixel value of the pixel (21) in the block (20) is represented, and q1 _i is the block boundary (1) in the corresponding first line (22) including the pixels (21, 23, 25, 27). ) Represents the pixel value of the pixel (23) of the neighboring block (20) that is second closest, and q2 _i is the corresponding first line (22) consisting of the pixels (21, 23, 25, 27). ) Represents the pixel value of the pixel (25) in the neighboring block (20) that is third closest to the block boundary (1).
| Q2 _i -2q1 _i + q0 _i |
A second decision value calculator configured to calculate a second filter decision value for the neighboring block (20) using only the pixel values q2 _i , q1 _i , and q0 _i based on (120),
The pixels (11, 13) in the block (10) to be filtered with respect to the block boundary (1) based on the first filter decision value calculated by the first decision value calculator (110). , 15, 17) a first pixel determiner (130) configured to determine the number of pixels in the first line (12) comprising:
Pixels (21, 21) in the neighboring block (20) to be filtered with respect to the block boundary (1) based on the second filter decision value calculated by the second decision value calculator (120). A second pixel determiner (140) configured to determine the number of pixels in the corresponding first line (22) comprising 23, 25, 27); A first comparator (180) configured to compare the first filter decision value calculated by the first decision value calculator (110) with a first threshold;
A second comparator (182) configured to compare the second filter decision value calculated by the second decision value calculator (120) with a second threshold;
Bei to give a,
The first decision value calculator (110) represents the pixel value of the pixel closest to the block boundary (1) in the first line having p0 ₀ of a plurality of pixels. , P1 ₀ represents the pixel value of the pixel second closest to the block boundary (1) in the first line composed of a plurality of pixels, and p2 ₀ represents the pixel composed of a plurality of pixels. in the first line, the represents the pixel value of the pixel that is adjacent to the third block boundary (1), p0 ₃ is a second line comprising a plurality of pixels of the block (10) Represents the pixel value of the pixel closest to the block boundary (1), and p1 ₃ is the second to the block boundary (1) in the second line composed of a plurality of pixels. It represents a pixel value of a pixel in proximity, p2 ₃ Do plurality of pixels Among consisting of the second line, when representing pixel values of pixels that are close to the third to the block boundary (1),
| P2 ₀ -2p1 ₀ + p0 ₀ | + | p2 ₃ -2p1 ₃ + p0 ₃ |
Is configured to calculate the first filter decision value as
The second determined value calculator (120) includes the neighboring block (20) closest to the block boundary (1) in the corresponding first line in which q0 ₀ includes a plurality of pixels. represents the pixel value of the pixel in the, q1 ₀ is in the first line of the corresponding a plurality of pixels, said block boundary (1) to the neighboring blocks in proximity to the second (20) represent the pixel values of the pixel, q2 ₀ is in the first line of the corresponding a plurality of pixels, said block boundary (1) to the neighboring blocks in proximity to the third (20) The pixel value of the pixel in the neighborhood, and q0 ₃ is the neighborhood closest to the block boundary (1) in the corresponding second line comprising a plurality of pixels in the neighborhood block (20) Pixel of pixel in block (20) Q1 ₃ represents the pixel value of the pixel in the neighboring block (20) that is second closest to the block boundary (1) in the corresponding second line composed of a plurality of pixels. , Q2 ₃ represent the pixel value of the pixel in the neighboring block (20) third closest to the block boundary (1) in the corresponding second line composed of a plurality of pixels. ,
| Q2 ₀ -2q1 ₀ + q0 ₀ | + | q2 ₃ -2q1 ₃ + q0 ₃ |
Is configured to calculate the second filter decision value as
Filtering control device (100) . The first pixel determiner (130) is: i) if the first filter decision value is less than the first threshold as determined by the first comparator (180), the block boundary Determine (2) that two pixels in the first line (12) consisting of the pixels (11, 13, 15, 17) in the block (10) are to be filtered, and ii ) If the first filter decision value is greater than or equal to the first threshold as determined by the first comparator (180), then the block boundary (1) is within the block (10) Configured to determine to filter one pixel in the first line (12) of pixels (11, 13, 15, 17);
The second pixel determiner (140) is: i) if the second filter decision value is less than the second threshold as determined by the second comparator (182), the block boundary It is determined that the two pixels in the corresponding first line (22) composed of the pixels (21, 23, 25, 27) in the neighboring block (20) are filtered with respect to (1). And ii) if the second filter decision value is greater than or equal to the second threshold as determined by the second comparator (182), the neighboring block (1) with respect to the block boundary (1) 20) is configured to determine to filter one pixel in the corresponding first line (22) consisting of the pixels (21, 23, 25, 27) in
The apparatus according to claim 4 . A first comparator (180) configured to compare the first filter decision value calculated by the first decision value calculator (110) with a first threshold;
A second comparator (182) configured to compare the second filter decision value calculated by the second decision value calculator (120) with a second threshold;
Further comprising
The first pixel determiner (130) is: i) if the first filter decision value is less than the first threshold as determined by the first comparator (180), the block boundary Determine (2) that two pixels in the first line (12) consisting of the pixels (11, 13, 15, 17) in the block (10) are to be filtered, and ii ) If the first filter decision value is greater than or equal to the first threshold as determined by the first comparator (180), then the block boundary (1) is within the block (10) Configured to determine not to filter pixels in the first line (12) of pixels (11, 13, 15, 17);
The second pixel determiner (140) is: i) if the second filter decision value is less than the second threshold as determined by the second comparator (182), the block boundary It is determined that the two pixels in the corresponding first line (22) composed of the pixels (21, 23, 25, 27) in the neighboring block (20) are filtered with respect to (1). And ii) if the second filter decision value is greater than or equal to the second threshold as determined by the second comparator (182), the neighboring block (1) with respect to the block boundary (1) 20) configured to determine not to filter the pixels in the corresponding first line (22) consisting of the pixels (21, 23, 25, 27) in
Apparatus according to claim 4 or 5 . i) determining the first threshold based on a quantization parameter associated with the block (10); ii) determining the second threshold based on a quantization parameter associated with the neighboring block (20). The apparatus according to any one of claims 4 to 6 , further comprising a threshold determiner (170) configured to: p0 _j represents the pixel value of the pixel (11) closest to the block boundary (1) in the first line (12) comprising the pixels (11, 13, 15, 17), and p1 _j represents the pixel value of the pixel (13) second closest to the block boundary (1) in the first line (12) comprising pixels (11, 13, 15, 17); Pixels in the neighboring block (20) closest to the block boundary (1) in the corresponding first line (22) where q0 _j is a pixel (21, 23, 25, 27) Represents the pixel value of (21), and q1 _i is second closest to the block boundary (1) in the corresponding first line (22) consisting of pixels (21, 23, 25, 27). It is assumed that the pixel value of the pixel (23) of the neighboring block (20) is Then
(9 × (q0 _j −p0 _j ) −3 × (q1 _j −p1 _j )) / 16
A first offset calculator (181) configured to calculate a first offset Δ based on
The first offset calculated by the first offset calculator (181) is applied to the block boundary (1) in the first line (12) consisting of pixels (11, 13, 15, 17). By adding to the pixel value of the pixel (11) that is closest to the block boundary (1) in the first line (12) consisting of pixels (11, 13, 15, 17) A first pixel corrector (190) configured to correct the pixel value of the closest pixel (11);
The first offset calculated by the first offset calculator (181) is used as the block boundary (1) in the corresponding first line (22) consisting of pixels (21, 23, 25, 27). ) Is subtracted from the pixel value of the pixel (21) in the neighboring block (20) that is closest to the corresponding first line of pixels (21, 23, 25, 27) ( 22) a second pixel modifier (22) configured to modify the pixel value of the pixel (21) in the neighboring block (20) closest to the block boundary (1). 192),
If the first filter decision value is less than the first threshold value as determined by the first comparator (180), the second value of p2 _j consisting of pixels (11, 13, 15, 17). If the pixel value of the pixel (15) that is the third closest to the block boundary (1) in the line (12) of 1 is represented,
(P0 _j + p2 _j -2p1 _j + 2Δ) / 4
A second offset calculator (183) configured to calculate a second offset based on
If the first filter decision value is less than the first threshold as determined by the first comparator (180), the second calculated by the second offset calculator (183). To the pixel value of the pixel (13) that is second closest to the block boundary (1) in the first line (12) comprising pixels (11, 13, 15, 17). The pixel of the pixel (13) that is second closest to the block boundary (1) in the first line (12) consisting of pixels (11, 13, 15, 17) by adding A third pixel corrector (194) configured to correct the value;
If the second filter decision value is less than the second threshold as determined by the second comparator (182), the correspondence q2 _j consists of pixels (21, 23, 25, 27) In the first line (22) that represents the pixel value of the pixel (25) in the neighboring block (20) that is third closest to the block boundary (1),
_{(Q0 j + q2 j -2q1 j} -2Δ) / 4
A third offset calculator (185) configured to calculate a third offset based on
If the second filter decision value is less than the second threshold as determined by the second comparator (182), the third offset calculated by the third offset calculator (185). In the neighboring block (20) that is second closest to the block boundary (1) in the corresponding first line (22) consisting of pixels (21, 23, 25, 27). By adding to the pixel value of the pixel (23), the block boundary (1) is second in the corresponding first line (22) consisting of pixels (21, 23, 25, 27). A fourth pixel corrector (196) configured to correct the pixel value of the pixel (23) in the neighboring block (20) in proximity;
The apparatus according to any one of claims 4 to 7 , further comprising: A third comparator (184) configured to compare a sum of the first filter decision value and the second filter decision value with a threshold;
The first pixel determiner (130) is less than the threshold so that a sum of the first filter determined value and the second filter determined value is determined by the third comparator (184). If there are pixels in the block (10) to be filtered with respect to the block boundary (1) based on the first filter decision value calculated by the first decision value calculator (110) 11, 13, 15, 17) configured to determine the number of pixels in the first line (12) comprising:
The second pixel determiner (140) is less than the threshold so that a sum of the first filter determined value and the second filter determined value is determined by the third comparator (184). If there are, pixels in the neighboring block (20) to be filtered with respect to the block boundary (1) based on the second filter decision value calculated by the second decision value calculator (120) Configured to determine the number of pixels in the corresponding first line (22) comprising (21, 23, 25, 27);
Apparatus according to any one of claims 4 to 8 . An encoder (40) comprising the filtering control device (100) according to any one of claims 4 to 9 . A memory (84) configured to store video frames;
An encoder (40) according to claim 10 , configured to encode the video frame into an encoded video frame;
The user equipment (80), wherein the memory (84) is further configured to store the encoded video frame. Decoder (60) comprising a filtering control device (100) according to any one of claims 4 to 9 . A memory (84) configured to store encoded video frames;
The decoder (60) according to claim 12 , configured to decode the encoded video frame into a decoded video frame;
A media player (86) configured to render the decoded video frame into a video data representation that can be displayed on a display (88);
User equipment (80) comprising: A computer program (74) for filtering control of a block (10) comprising a plurality of pixels (11, 13, 15, 17) in a video frame in which each pixel (11, 13, 15, 17) has a respective pixel value. And when the computer program runs on the computer (70), the computer program (70)
p0 _i is a plurality of pixels (21, 23, 25, 27) in the video frame in the first line (12) consisting of pixels (11, 13, 15, 17) in the block (10). Represents the pixel value of the pixel (11) closest to the block boundary (1) to the neighboring block (20) consisting of the first line, where p1 _i is composed of the pixels (11, 13, 15, 17) In (12), the pixel value of the pixel (13) that is second closest to the block boundary (1) is represented, and p2 _i is composed of the pixels (11, 13, 15, 17). In the line (12), if it represents the pixel value of the pixel ( 15 ) third closest to the block boundary (1),
| P2 _i -2p1 _i + p0 _i |
To calculate a first filter decision value for the block (10) using only the pixel values p2 _i , p1 _i , and p0 _i ,
The neighborhood where q0 _i is closest to the block boundary (1) in the corresponding first line (22) consisting of the pixels (21, 23, 25, 27) in the neighborhood block (20) The pixel value of the pixel (21) in the block (20) is represented, and q1 _i is the block boundary (1) in the corresponding first line (22) including the pixels (21, 23, 25, 27). ) Represents the pixel value of the pixel (23) of the neighboring block (20) that is second closest, and q2 _i is the corresponding first line (22) consisting of the pixels (21, 23, 25, 27). ) Represents the pixel value of the pixel ( 25 ) in the neighboring block (20) that is third closest to the block boundary (1),
| Q2 _i -2q1 _i + q0 _i |
To calculate a second filter decision value for the neighboring block (20) using only pixel values q2 _i , q1 _i , and q0 _i ,
Based on the first filter decision value, the first line (12) of pixels (11, 13, 15, 17) in the block (10) to be filtered with respect to the block boundary (1) Let me determine the number of pixels inside,
A corresponding first line (21, 23, 25, 27) consisting of pixels (21, 23, 25, 27) in the neighboring block (20) to be filtered with respect to the block boundary (1) based on the second filter decision value. 22) comprising code means for determining the number of pixels in
The number of pixels in the first line (12) consisting of the pixels (11, 13, 15, 17) in the block (10) to be filtered is determined by the first filter determination value and the first filter determination value. The first line (12) consisting of the pixels (11, 13, 15, 17) in the block (10) to be filtered with respect to the block boundary (1) based on the comparison of the threshold values of 1 (S20) And determining the number of pixels in
The determination of the number of pixels in the corresponding first line (12) consisting of the pixels (21, 23, 25, 27) in the neighboring block (20) to be filtered is determined by the second filter decision. The corresponding consisting of the pixels (21, 23, 25, 27) in the neighboring block (20) to be filtered with respect to the block boundary (1) based on the comparison of the value and the second threshold (S23) Determining the number of pixels in the first line (22) ;
The step (S1) of calculating the first filter determination value includes the pixel of the pixel closest to the block boundary (1) in the first line in which p0 ₀ is composed of a plurality of pixels. P1 ₀ represents the pixel value of the pixel second closest to the block boundary (1) in the first line composed of a plurality of pixels, and p2 ₀ represents a plurality of pixels Represents the pixel value of the pixel that is third closest to the block boundary (1) in the first line consisting of: p0 ₃ is the number of pixels in the block (10). 2 represents the pixel value of the pixel closest to the block boundary (1), and p1 ₃ represents the block boundary (1) in the second line composed of a plurality of pixels. Represents the pixel value of the second closest pixel, p ₃ is in the second line comprising a plurality of pixels, when representing pixel values of pixels that are close to the third to the block boundary (1),
| P2 ₀ -2p1 ₀ + p0 ₀ | + | p2 ₃ -2p1 ₃ + p0 ₃ |
A step (S1) of calculating the first filter decision value as
The step (S2) of calculating the second filter decision value includes the neighboring block closest to the block boundary (1) in the corresponding first line in which q0 ₀ is composed of a plurality of pixels. represents the pixel value of the pixel in the (20), q1 ₀ is in the first line of the corresponding a plurality of pixels, the neighboring block which is close to the second to the block boundary (1) represents the pixel value of the pixel of (20), q2 ₀ is in the first line of the corresponding a plurality of pixels, said block the neighboring blocks in proximity to the third to the boundary (1) ( represents the pixel value of the pixel in the 20), in the second line corresponding q0 ₃ consists of a plurality of pixels of the neighboring blocks (20), closest to the block boundary (1) The neighboring block (2 0) represents the pixel values of the pixels in, q1 ₃ is in the second line the corresponding a plurality of pixels, said block boundary (1) to the neighboring blocks in proximity to the second (20) The pixel in the neighboring block (20) that is third closest to the block boundary (1) in the corresponding second line consisting of a plurality of pixels is represented by the pixel value of q2 ₃ If the pixel value of
| Q2 ₀ -2q1 ₀ + q0 ₀ | + | q2 ₃ -2q1 ₃ + q0 ₃ |
A step (S2) of calculating the second filter decision value as
Computer program (74). 請 Motomeko 14 computer-readable storage medium storing a computer program (74) according to (73).

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